140+ Must-Know Email Marketing Terms for Every Marketer

Whether you're new to email marketing or have been in the field for quite some time now, you must be aware of the common terminologies and concepts to be successful. While the email marketing sector is a rapidly evolving one, and there’s something new to learn about every day, there are some terms that you can’t miss out on. To help you, we have compiled a comprehensive email marketing glossary of 147 key email marketing terms you need to know. So let’s get started.

147 email marketing terms you need to know

Here’s the curated list of email marketing terms you must know if you aspire to be an email marketer or are already an email marketer.

| A | B | C | D| E | F | G | H | I | J | K | L| M| N| O | P | Q | R | S| T | U | V | W | X | Y | Z |

A/B testing

A/B testing also known as split testing, this is a method for comparing two versions (A and B) of an email element (such as a subject line, design, or CTA) with a subset of your audience to determine which performs better based on key metrics (e.g., open rates, click-through rates). The winning version is then sent to the rest of the list.

AMP emails

Emails that use the AMP (Accelerated Mobile Pages) framework to allow for interactive and dynamic content within the email itself, such as carousels, forms, and up-to-date information, without needing to visit a separate web page.

API (Application Programming Interface)

A set of rules that allows different software applications to communicate and exchange data with each other, often used in email marketing for automating tasks like adding new subscribers or sending transactional emails.

Acceptance rate

The percentage of emails sent that are accepted by the recipient's email server (ISP) without bouncing. A high acceptance rate indicates good email infrastructure and sender reputation.

Accessibility

The practice of designing and coding emails to be usable and understandable by everyone, including those using assistive technologies.

Alternate text (alt text)

The practice of designing and coding emails so that they are easily usable and understandable by everyone, including individuals with disabilities (visual, auditory, cognitive, or motor).

Attachment

A file that is sent along with an email. Should be avoided in most marketing campaigns for security purposes.

Audience fatigue

A phenomenon where subscribers become disengaged or stop responding to emails because they are receiving too many messages or the content is no longer relevant, often leading to increased unsubscribes or spam complaints.

Authentication

The process of verifying the sender of an email using standards like SPF, DKIM, and DMARC to prove the message is legitimate and prevent spoofing.

Autoresponder

An automated email or a sequence of emails sent to a subscriber after a specific trigger, such as signing up for a newsletter or making a purchase.

BIMI (Brand Indicators for Message Identification)

An email specification that allows organizations to display their brand logo next to their "from" name in the recipient's inbox, provided their emails are properly authenticated.

Behavioral email

Emails sent to subscribers based on their specific actions or inactions (behavior) with a website or previous emails, such as abandoning a cart or clicking a specific link.

Behavioral segmentation

The process of dividing an email list into smaller groups based on their behaviors, actions, or engagement levels to send more targeted and relevant content is known as behavioral segmentation.

Blacklist

A real-time database of IP addresses or domains that have been reported for sending spam or other malicious emails. Emails sent from a blacklisted address are often rejected by email servers.

Blacklist monitoring

The ongoing process of checking various blacklists to see if a sender's IP address or domain has been listed, allowing for prompt action to protect sender reputation and deliverability.

Blocked contacts

Subscribers who have been intentionally or automatically prevented from receiving further emails, often due to a history of hard bounces or spam complaints.

Blocked rate

The percentage of emails that were rejected outright by the receiving server due to factors like poor sender reputation or blacklisting.

Body copy

The main text content of an email message, distinct from the subject line, header, or footer.

Border

A visual line or frame used in email design to separate different sections or elements, helping to structure the content.

Bounce rate

The percentage of total emails sent that could not be successfully delivered to the recipient's inbox. This is further divided into hard bounces and soft bounces.

CAN-SPAM act

A U.S. law that establishes rules for commercial email and commercial messages, giving recipients the right to have emails stopped from being sent to them and outlining strict penalties for violations.

CASL

Canada's Anti-Spam Legislation, which dictates how email marketers must gain, record, and maintain consent from Canadian subscribers.

CSS (Cascading Style Sheets)

A coding language used to define the visual presentation and styling of an HTML email, including fonts, colors, and layout.

Call-to-action (CTA)

A button, link, or phrase in an email that prompts the recipient to take a specific action, such as "Shop Now," "Read More," or "Download Now".

Capped frequency

A feature in email platforms that limits the number of emails a single subscriber can receive within a specific time frame, helping to prevent audience fatigue.

Carousel

An interactive element within an email that allows a user to swipe or click through a sequence of images or content blocks.

Click map

A visual representation or tool that shows where recipients click within an email design, highlighting popular and underperforming areas.

Click-through rate (CTR)

The percentage of total recipients who clicked on one or more links in an email.

Click-to-Open Rate (CTOR)

A more accurate measure of engagement than CTR, calculated by dividing unique clicks by unique opens. It assesses the quality of the email's content and CTA.

Complaint

When a recipient marks an email as "spam" or "junk" through their email client, which is reported back to the sender's email service provider (ESP) and impacts sender reputation.

Conditional block

A segment of content within an email that is only displayed if certain predefined criteria about the recipient are met.

Consent management

The process of collecting, storing, and updating user permissions, ensuring compliance with privacy laws like GDPR and CAN-SPAM.

Conversion funnel

A multi-step process that maps the customer journey from initially receiving an email to completing a desired action, such as a purchase or sign-up.

Conversion rate

The percentage of email recipients who complete a desired action (conversion event) after opening and interacting with an email.

Custom events

Specific actions or behaviors (e.g., "viewed pricing page," "added item to cart") defined and tracked by a business to trigger targeted email automation.

DKIM (Domain Keys Identified Mail)

An email authentication method that adds a digital signature to emails, verifying that the email was sent from the specified domain and that its content hasn't been altered.

DMARC

Domain-based Message Authentication, Reporting, and Conformance is an email authentication protocol that uses both SPF and DKIM to give ISPs rules on how to handle emails that fail authentication (e.g., reject them or mark them as spam).

Dark mode

A color scheme preference available in some email clients where the display uses light text on a dark background.

Dedicated IP

An exclusive IP address used by a single sender to send all their emails. This gives the sender complete control and responsibility over their sender reputation.

Delay send

A feature that allows an email marketer to schedule an email to be sent at a later date or time, often used in Send Time Optimization (STO) strategies.

Delivered rate

The percentage of emails that were successfully delivered to the recipient's mail server after filtering out bounces.

Demographics

Specific characteristics of an audience, such as age, gender, location, and income, used for email segmentation and personalization.

Domain reputation

The trust level associated with your sending domain (e.g., yourcompany. com) as perceived by mailbox providers; highly influential on deliverability.

Double opt-in

A two-step subscription process where, after signing up, a user receives a confirmation email and must click a link within it to be added to the email list. This ensures a high level of consent and list hygiene.

Drip campaign

A series of automated, pre-written emails sent to subscribers over time in a predefined sequence to nurture leads, onboard new users, or promote products.

Dynamic content

Email content that automatically changes based on the individual recipient's data, preferences, or behavior, allowing for highly relevant and personalized messages within a single email template.

Email alias

An email address that forwards messages to another, real email account, often used for organizational purposes (e.g., info@example. com forwarding to an employee's inbox).

Email analytics

The measurement and analysis of data related to email campaigns, including metrics like open rate, click-through rate, and conversions, to optimize future sends.

Email appending

The practice of adding email addresses to an existing customer database using third-party services, often a risky practice that can lead to deliverability issues.

Email automation

The use of software to send predefined emails automatically based on triggers, schedules, or subscriber actions, streamlining the marketing process.

Email cadence

Refers to how often you send campaigns to subscribers; balancing frequency is key to avoiding fatigue and maximizing engagement.

Email campaign

A coordinated set of email messages designed to achieve a specific marketing goal, such as promoting a sale, launching a new product, or providing a newsletter.

Email client

The software or web application used to access and read emails, such as Outlook, Gmail, Apple Mail, or Yahoo Mail.

Email deliverability

The ability of an email to reach the intended recipient's inbox (rather than the spam folder or being blocked entirely), influenced by sender reputation, content, and authentication.

Email fatigue score

A metric or analysis that indicates how close a subscriber is to becoming overwhelmed or fatigued by the volume of emails received, suggesting a need to adjust send frequency.

Email footers

The bottom section of emails containing brand, legal, and unsubscribe details; proper footers ensure compliance and build trust.

Email frequency optimization

The practice of adjusting sending frequency based on each user’s engagement; highly active users may get more emails, while fatigued users get fewer.

Email header

The top section of an email containing the "from" name, subject line, and often a preheader, as well as the main brand logo.

Email journey

The complete path or sequence of emails a subscriber receives over time, often created visually using a workflow builder.

Email list

A database of email addresses and associated subscriber information (e.g., names, demographics) collected with permission, used for sending marketing campaigns.

Email precedence

An email header field used in replies or forwards that helps email clients correctly thread conversations and apply rules to automated messages.

Email preference center

A page where subscribers choose what emails they want and how often, reducing unsubscribes by giving users more control.

Email preview text

The short snippet shown next to the subject line in the inbox, which boosts open rates by summarizing or teasing the email content.

Email reputation

A score assigned to an email sender (IP and domain) by ISPs based on factors like spam complaints, bounce rates, and email volume. A good reputation is crucial for deliverability.

Email segmentation

The process of dividing an email list into smaller, targeted groups based on shared characteristics to send more personalized and relevant content, improving engagement and conversions.

Email service provider (ESP)

A company that provides the software and infrastructure for sending and managing email marketing campaigns

Email signature

A block of text at the end of an email that provides the sender's name, title, and contact information, often personalized.

Email template

A pre-designed HTML structure for emails that can be easily customized with content and images, ensuring consistency and efficiency in campaign creation.

Engagement

How recipients interact with emails, measured by metrics like open rates, click-through rates, unsubscribes, and spam complaints.

Engagement rate

A holistic metric combining opens, clicks, and occasionally replies, reflecting the overall health and responsiveness of a segment.

Engagement recency

A segmentation approach that groups subscribers based on how recently they last engaged with an email (opened or clicked), allowing marketers to target active users and re-engage inactive ones.

Exposure rate

The percentage of emails that are actually seen by the recipient, which is often estimated based on factors like deliverability and inbox placement.

Fallback email

A plain-text or simplified HTML version of an email that is displayed if the recipient's email client cannot render the full, rich HTML version.

First-party data

Data collected directly from a brand's own audience or customers through sign-up forms, purchases, and direct interactions, which is highly valuable for personalization and segmentation.

Forward

When an email is sent from one recipient to another, often via a manual forward or an "Email to a Friend" link.

GDPR (General Data Protection Regulation)

A comprehensive data privacy law in the European Union that regulates how personal data is collected and processed, requiring explicit consent for email marketing.

Geo-targeting

Sending campaigns based on a subscriber’s geographic location, useful for local sales, events, or region-specific content.

Greylisting

A temporary email rejection technique used by ISPs to combat spam. Legitimate email servers will try again later (soft bounce), while spammers typically will not, thus filtering them out.

HTML (HyperText Markup Language)

The standard coding language used to design and structure emails, allowing for images, specific layouts, and interactive elements.

HTML Editor

A tool within an ESP that allows users to write or modify the underlying HTML code of an email, used for complex customization.

Hard bounce

A permanent reason an email cannot be delivered, such as an invalid or non-existent email address. These addresses should be immediately removed from the email list to protect sender reputation.

Honey pot

A false email address intentionally placed online to collect addresses used by spammers. Sending emails to a honey pot address can result in an immediate blacklisting.

Hybrid segmentation

Combining multiple data points (e.g., demographics and behavior) to create highly specific and precise subscriber groups.

IP warming

The process of gradually increasing the volume of emails sent from a new, "cold" IP address over several weeks to build a positive sending reputation with ISPs.

ISP (Internet Service Provider)

The company providing internet access (e.g., Gmail, Outlook, Yahoo Mail), which uses complex filters and reputation scores to decide which emails to deliver and which to block or mark as spam.

Image stacking

The design technique of laying out images in a single vertical column for mobile display to ensure proper rendering.

Image-to-text ratio

The balance between the number of images and the amount of text in an email; a low ratio (more text) is often preferred by spam filters.

Inbox placement rate

The percentage of emails that successfully land in the recipient's primary inbox, as opposed to the spam/junk folder or being blocked entirely.

Integration

The connection between an email service provider and other software (e.g., CRM, e-commerce platform) to share data and automate processes.

Interactive emails

Emails that include elements users can interact with directly within the inbox, such as carousels, forms, and quizzes, without leaving their email client.

Lead magnet

A piece of valuable content (e.g., an ebook, whitepaper, discount code, webinar) offered for free in exchange for a subscriber's email address.

Lead nurturing

The process of building relationships with potential customers (leads) through targeted, relevant content delivered via email to guide them toward a purchase or desired action.

Link wrapping

The process where an ESP replaces a regular link with a unique tracking link to monitor clicks and engagement statistics.

List bombing

A malicious attack where an automated bot signs up a single email address to hundreds of mailing lists, overwhelming the inbox.

List churn

The natural process of subscribers unsubscribing or addresses bouncing from an email list over time, highlighting the need for continuous list growth and hygiene.

List hygiene

The practice of regularly cleaning and updating an email list by removing invalid, bounced, or unengaged contacts to maintain list quality and improve deliverability and sender reputation.

MIME Type (Multipurpose Internet Mail Extensions Type)

A standard used to indicate the nature and format of a file or content, such as specifying that an email contains both an HTML version and a plain-text version.

Martech

The broad term for the technology, tools, and platforms that power marketing programs (short for Marketing Technology).

Merge tags

Also known as personalization tags, are placeholders in emails, forms, or other messages that are automatically replaced with specific recipient data, like a name or address, when the message is sent.

Multivariate testing

A more complex testing method than A/B testing where multiple elements within a single email are tested simultaneously to understand how they interact and which combination yields the best results.

NPS (Net Promoter Score)

A metric used to gauge customer loyalty and satisfaction by asking a simple question: "How likely are you to recommend our company/product to a friend or colleague?"

NPS Email

An email campaign designed specifically to collect the Net Promoter Score (NPS) feedback from subscribers.

Open rate

The percentage of recipients who open a specific email, calculated as unique opens divided by the number of emails delivered.

Open tracking pixel

A tiny, invisible 1x1 pixel image embedded in an HTML email. When the image is loaded, it registers that the email has been opened.

Opt-in

The action a user takes to explicitly give permission to a brand to send them emails, ideally using a double opt-in process.

Opt-out

The action a subscriber takes to unsubscribe or stop receiving emails from a sender, typically via an unsubscribe link in the footer.

Padding

Empty space or margin added around the content within an email element to control layout and readability.

Personalization

The practice of tailoring email content, subject lines, and offers to individual subscribers based on their data, preferences, and behavior, making messages more relevant.

Phishing

A malicious activity where fraudulent emails are sent to trick recipients into revealing sensitive information (passwords, credit card numbers) by impersonating a legitimate brand.

Plain text emails

Emails that contain only text with no formatting, images, or hyperlinks (though URLs are present). They are highly deliverable and essential for accessibility.

Preference tagging

Applying specific labels or tags to subscribers based on their expressed interests or preferences, allowing for highly targeted segmentation and personalized content delivery.

Preview mode

A feature that shows how an email appears before sending, helping fix formatting issues across devices.

Primary inbox

The main folder in an email client (especially Gmail) where standard emails land. Marketers strive for primary inbox placement to maximize visibility, as emails in the 'Promotions' or 'Spam' tabs are less likely to be opened.

Primary, secondary and tertiary button

A design hierarchy for CTAs within an email. The primary button is the main, most prominent call to action, while secondary and tertiary buttons offer less important or alternative actions.

Quality score

A metric used by search engines (like Google Ads) to determine ad ranking, which is less relevant to email marketing but the principle of quality scoring is similar to sender and domain reputation scores used by ISPs.

RSS (Really Simple Syndication)

A web feed format used to publish frequently updated content (like blog posts). Some ESPs can automatically generate emails from an RSS feed..

Re-engagement campaign

A specific automated workflow sent to inactive subscribers to encourage them to open, click, or update their preferences before they are removed from the list.

Real-time personalization

Email content that updates at the moment a user opens it, such as live pricing, countdown timers, and weather-based content.

Render testing

The process of checking how an email displays across dozens of different email clients (Gmail, Outlook, Apple Mail) and devices.

Responsive design

An email design approach where the layout and elements of the email adapt automatically to the screen size of the device it's being viewed on (desktop, tablet, mobile), ensuring a good user experience.

Return on investment (ROI)

A performance metric used to evaluate the profitability or efficiency of an email campaign, generally showing how much revenue was generated for every dollar spent on the campaign.

Revenue Per Email (RPE)

Measures how much revenue each individual email generates, helping compare campaign performance and optimize ROI.

SMTP (Simple Mail Transfer Protocol)

The standard communication protocol for sending electronic mail over the internet.

SPF (Sender Policy Framework)

An email authentication method that allows a domain owner to specify which mail servers are authorized to send emails on their behalf, helping to prevent spoofing.

Seed list

A small, internal list of email addresses used by the sender to test deliverability, rendering, and placement before sending the email to the main audience.

STO (Send Time Optimization)

Using algorithms to determine the best time for each individual to receive an email for maximum open probability, synonymous with Adaptive Sending.

Sender score

A numerical rating (0–100) showing your email sending reputation; a low score indicates high spam complaints or poor practices.

Service-based email

A classification often used by ESPs for essential, non-promotional emails (e.g., password reset, receipt), allowing them to bypass preference center settings.

Shared IP

An IP address used by multiple senders, where the reputation is influenced by the sending practices of all users on that IP.

Single opt-in

A one-step subscription process where a user is immediately added to the email list after submitting a sign-up form, without needing to confirm their email address via a follow-up email. It typically results in larger lists but lower quality subscribers.

Soft bounce

A temporary delivery issue, such as a full inbox, a temporary server issue, or the email being too large. ISPs will typically attempt to re-send the email over a period of time.

Spam

Unsolicited commercial email (UCE) or junk mail sent to a large number of recipients, often promotional and a major concern for ISPs and recipients.

Spam filter

Software used by ISPs and email clients to identify and block or divert unwanted spam emails into a junk folder based on content, sender reputation, and authentication status.

Spam trap

An email address used to catch spammers or careless senders; hitting spam traps damages sender reputation significantly.

Subject line

The line of text that appears in the recipient's inbox and provides a preview of the email's content, a key factor in determining if an email is opened.

Submission rate

The percentage of emails that an ESP accepts for sending out of the total emails attempted to be sent.

Subscriber

An individual who has opted into receiving emails from a brand or organization.

Subscriber lifecycle

The stages a customer goes through, from initial opt-in to loyal customer to re-engagement/churn; used to map automated workflows.

Sunset policy

A defined rule for automatically removing subscribers who have been inactive for a certain, long period (e.g., 12 months) to maintain list health.

Suppression list

A segment of addresses that should never be sent emails (e.g., known spam traps, hard bounces, or global unsubscribes).

Transactional email

These are messages sent to individual recipients and are triggered by a transaction or specific actions or interactions on a website or application.

Trigger email

This is an automated message sent in response to a specific action taken by a subscriber.

Unsubscribe rate

The percentage of recipients who click the unsubscribe link in an email, indicating a need to reassess content relevance, frequency, or audience targeting.

WYSIWYG editor (What You See Is What You Get)

A visual email editor that allows users to design emails using drag-and-drop or visual interfaces, and the resulting display during editing closely mirrors the final output the recipient will see.

Webhook

A method for applications to communicate in real-time by sending automatic information updates over the web, often used to trigger actions in an ESP based on events in another system (e.g., a purchase in an e-commerce store).

Whitelist

A list of trusted senders whose emails are automatically accepted into the inbox, bypassing most spam filters. Senders strive to be whitelisted by their subscribers and ISPs.

Widgets

Interactive elements or mini-applications that can be embedded within an email using AMP technology or other coding, offering enhanced functionality.

Conclusion

Mastering key email marketing terms is very important to achieve success in email marketing. Understanding these terminologies, which range from basic ideas to technical aspects, improves knowledge and helps marketers design effective campaigns while staying legally compliant.