Email Marketing Glossary for Retailers | Essence of Email

Email Marketing Glossary

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A/B Test – an experimental test consisting of a control and an experimental group. The purpose of A/B tests is to pinpoint if certain changes have a significant impact on target metrics/KPI’s.

Alt Text – the HTML text that shows up in place of an image if an image is blocked.

Animated GIF – an image file in GIF format that can be rendered to produce short animations by looping several frames of the image. Since email clients have difficulty rendering video, animated GIFs are often used to infuse some moving imagery into marketing emails.

API (Application Programming Interface) – a set of programming standards that allow for software to connect to and interact with each other.

Authentication – the process that email undergoes to identify the sender of an email with the email message being sent. Authentication plays a part in ISP servers accepting or rejecting your mail. Two common authentication frameworks are DKIM and SPF.

Automated Series – a set of automated emails set to send in relation to each other. A drip campaign is an example of an automated series.

Autoresponder – an email that is automatically sent based on a pre-determined set of conditions. Autoresponders can be set to trigger based off of a variety of conditions such as user signup, site browse behavior, birthdays, email interaction, etc. Autoresponders are an integral part of any well-run email marketing program. Also see Triggered Email.


Blacklist – a list maintained by industry groups or ISP’s internally of bad senders. Being blacklisted will hurt your deliverability.

Blocked – a form of bounced email where the ISP does not deliver you email due to spam filtering or block lists. Sometimes referred to as a block bounce, other times categorized under the umbrella of soft bounce.

Bulletproof Button – a HTML-styled “button”. This is essentially a link styled with a display:block and a background color. Although their styling can’t match an image-based button, bulletproof buttons are widely used because they are visible with images turned-off (a default in many email clients).


Cadence – the overall pattern of your email campaigns, identified by the “rhythm” of your emails. Though technically different, often times frequency and cadences are used interchangeably by marketers.

Call-to-Action (CTA) – a pointed directive to a contact to drive a specific action. “Shop Now” is an example of a CTA.

Campaign – a singular send of a marketing email.

CAN-SPAM – the pivotal legislation in the United States governing the sending of emails.

Cart Abandonment Email – emails sent to a contact that “abandons” his/her shopping cart. Emails can be sent in real-time or on a set delay.

Click-Through – the action of clicking through one of the links in your emails.

Click-Through Rate (CTR)– the percentage of your delivered emails that get at least one click. CTR = Unique Clicks / Delivered

Complaint – a complaint from your subscribers either in the form of click the spam button on one of your emails or through replying/contacting you directly telling you they no longer wish to receive your emails.

Complaint Ratio – the ratio of spam complaints (number of people marking your emails as spam) you receive on each outgoing email campaign compared to the total volume of emails you sent.
Complaint Ratio = Number of spam complaints / Email volume sent

Conversion Rate – the rate at which your email campaigns convert (generally refers to the purchase). Conversion Rate = Conversions / Clicks.

Cookies – a piece of tracking code that populates a website visitor’s browser. Cookies are used for tracking, attribution, and retargeting efforts.


Dedicated IP – a sender IP address that is specifically dedicated to you as an email sender. Dedicated IP’s are different from shared IP’s in that they are set up exclusively for your use rather than shared across multiple senders.

Deferred – email that has neither been accepted nor rejected by the recipient mail server. Deferred emails are retried several times over a time period, at which point it is accepted during the process or rejected at the end.

Deliverability – a general term used to describe how likely your emails will get delivered to your subscribers’ inboxes.

Delivery Rate – the percentage of your outgoing emails that were “delivered”, or not rejected by the ISP servers. Not to be confused with inboxing rate.

Dirty List – term used to refer to an email list that is composed of many bad addresses, such as inactive contacts, spam traps, fake addresses, etc.

Disengaged – a categorization that defines subscribers who have not engaged with your email marketing efforts in a set time frame. For example, a subscriber may be considered disengaged if he/she has not opened or clicked any of your emails in the last 6 months. There’s no objective definition of disengaged, and can vary widely depending on your list composition and industry vertical. Also see Dormant, Inactive.

Domain Keys Identified Mail (DKIM) – an authentication method that links a sender domain to the email message sent. Used by the major ISP’s to identify mail, DKIM is an important form of authentication for email.

Domain Reputation – the reputation associated with your sending domain or subdomain. Domain reputation plays a part in determining your overall sender reputation and thus your deliverability.

Dormant – see Disengaged.

Double Opt-In – the method of subscribing a contact to your email list where a confirmation email is sent to a contact. The contact must take a specific action (usually clicking on an unique link) to indicate they want to be on your email list. Only then are they onboarded onto your list.

Drip Campaign – a series of automated emails that are sent in a specific sequence after a user-initiated event. Common drip campaigns include customer welcome campaigns, post-purchase campaigns, and re-engagement campaigns.

Dynamic Content – pieces of content in your emails that are dynamically called based on a certain logic criteria set. Dynamic content is useful in personalizing your content, since you can select what version your contacts see based on various behavioural or historical data points.


Email Client – a program used to interface with the email server in order to read, send, and organize email. Email clients are divided by web-based clients (also known as webmail) and desktop-based clients. Microsoft Outlook and Thunderbird are two examples of desktop-based clients.

Email Service Provider (ESP) – a technology platform designed primarily to manage your email marketing efforts. An ESP allows you to easily create email campaigns and send them to your email list. ESP’s vary in their features and functionalities, but typically provide segmentation, reporting, authentication, API access, and automation services for your emails.

Engagement – a term referring to an email subscriber’s level of interaction with your emails. Factors that show user engagement include opening, clicking, whitelisting, and starring your emails.


Footer – the bottom navigation, disclaimers, icons, and other elements that remain consistent in your email templates across multiple campaigns.

Frequency – the rate of email campaigns sent over a given time period.


Hard Bounce – a permanent rejection by the recipient mail server of your email. There are several reasons for hard bounces, with the primary reason being an invalid email address (misspelling, deleted, or fake email address). High hard bounce ratios negatively affect your deliverability.

Header – the top navigation, logo, SWYN, and other elements that remain consistent in your email templates across multiple campaigns.

Hero Image – the main, large image in your email.

Images Off – the default view in many email clients, which blocks images from rendering unless the contact specifically selects otherwise.


Inboxing Rate – the rate at which your outgoing emails reach the email inboxes of your subscribers.

Internet Service Provider (ISP) – in the email marketing industry, used to refer to providers of webmail such as Gmail, Yahoo!, AOL, and Hotmail.

IP Reputation – the reputation associated with your sender IP address. Your sender reputation relies heavily on your IP reputation, since your sender IP serves as a “name” identifying you as a sender.


List Attrition – the loss of contacts on your email list. This can be due to spam complaints, hard bounces, repeated soft bounces, or unsubscribes.

List Cleaning – the process of suppressing, unsubscribing, or otherwise removing bad email addresses from your email list. Regular list cleaning is a good practice to maintain high deliverability marks.

List Fatigue – the gradual disengagement and dropping off of your email list. List fatigue can be seen in greater numbers of inactive contacts and more unsubscribing contacts.

List Growth – the process of increasing email subscribers to your list.

List Rental – sending to an email list owned by a third-party. List rental differs from list purchase in that you never see the email address list. Rather, the third-party vendor sends your email on your behalf to their list.


Manage Preferences Center – a form residing on your website where email subscribers can manage their preferences (frequency, contact information, mailing lists, etc). The data is passed from the manage preferences form to your email service provider, which can be used for segmentation and targeting.

Marketing Emails – emails with strong commercial intent. Marketing emails are distinct from transactional emails, which focus on non-marketing messages such as confirming an order, shipment information, or password reset.

Mosaic – the process of creating pixelated substitutions of images using HTML styling and tables in order to be visible with images off.


Onboarding – the process of bringing on new email contacts to your email list. Generally, new contacts are evaluated during a scrutiny “onboarding” period before considered fully active members of your email list.

Open Rate – the percentage of your email messages that your subscribers opened relative to the total number you sent. Open rate = Unique opens / Delivered.

Opt-Out – to indicate that future email messages are unwanted from a particular email sender. Contacts who “opt-out” from email mailing lists no longer wish to receive email from a particular sender. Also see Unsubscribe.

Overlay Capture – a method of capturing email addresses by serving an on-site overlay prompting website visitors to subscribe to your email list.


Partnership Campaigns – an email campaign rule with a complementary industry partner to cross-promote products or services to each other’s email lists. Partnership campaigns can be useful in email list growth and brand exposure.

Pre-header – the first lines of text in an email. In certain email clients, pre-header text is shown as supplementary text to the subject line. Email marketers can leverage this added “real estate” to add supporting messaging to their email subject lines to further entice subscribers to open the email.


Re-Engagement Campaign – a special series of emails sent to disengaged or inactive contacts with the purpose of getting a portion of them to engage (open/click). Re-engagement campaigns go hand in hand with maintaining a clean list, since usually those inactive contacts who don’t respond at the end of the series will be suppressed from future sends or unsubscribed by the retailer. Also known as Reactivation Campaign, Win-Back Campaign.

Reactivation – see Re-Engagement Campaign.

Retargeting – the process of issuing additional marketing touches to a contact based on a past behavioral action. For example, if you visit a particular product page and then later get hit with a display ad showing that product, chances are you have been retargeted.

Revenue/Delivered – total revenue divided by number of delivered emails. This metric gives you a gauge of how well your email performed (revenue-wise) relative to the amount you sent out. Since it is an “per capita” adjusted revenue, you can more easily compare across different email campaigns to judge the effectiveness of each.

Reverse Append – the process of obtaining missing email addresses when you have other contact information such as name, address, phone number, etc. Reverse appends work by using a third-party who maintains large databases of contacts to cross-reference your existing list to garner email address information.

RFM Analysis – RFM stands for “Recency, Frequency, Monetary”. This is a framework for developing marketing strategy based on three key components categorizing customers or contacts.


Secondary Banner – a smaller “banner” image incorporated in your email templates that push a call-to-action different from the main call-to-action of your email campaign. Secondary banners can be used in a variety of ways, such as promoting top categories, seasonal ongoing sales, contests, and more.

Seed List – a list of email addresses included on email campaigns sent regardless of exclusions. Seed lists are not email address of your actual email subscribers, but rather a “test” list of inboxes that either you or a third-party owns. The primary purpose of a seed list is to estimate inboxing rates.

Send Time Optimization – the process of optimizing what time during the day you send out your emails to achieve the highest desired metrics.

Send Time Personalization – the process of optimizing the send time of your email campaigns so that each email is deployed to a contact at the time that the contact is most likely to open emails.

Sender Policy Framework (SPF) – an authentication method that prevents spoofing by verifying sender IP addresses of incoming mail. SPF and DKIM authentication are commonly used by ISP’s in evaluating incoming mail.

Sender Reputation – your reputation as an email sender. The better your sender reputation is, the better your deliverability.

SenderScore – a measure of sender reputation issued by ReturnPath, a leading provider of deliverability services. SenderScore is provided on a non-linear scale of 0 to 100, with 100 being the best. You can get your free SenderScore by registering on

Signup Source – the source where an email address is captured. This can be from opt-in at checkout, through a website overlay, signup box on a blog, at point of sale for bricks & mortar locations, social media, physical events, etc.

Single Opt-In – the method of subscribing a contact to your email list without a follow up email confirming they want to be opted-in.

SMTP (Simple Mail Transfer Protocol) Server – a server used to handle outgoing mail.

Soft Bounce – a temporary rejection by the recipient mail server of your email. Some soft bounce reasons include recipient’s mailbox is full, temporary server down time, email message is too large.

Spam Trap – an email address designed to catch bad senders. Spam traps are either “fake” email addresses spam-fighting associations release (but are never manually subscribed) or very inactive email address that ISP’s turn into traps. If you send email to a spam trap, known as “hitting” a spam trap, you will suffer an immediate and heavy drop in your deliverability.

Subject Line – the title of an email that acts as a descriptive identifier of the email’s subject. Visible without opening the email.

Subscriber – a contact who is part of your email list.


Test List – an internally maintained list of email addresses. Test lists are useful for testing email rendering for issues prior to sending out a live email campaign.

Text-to-Image Ratio – the ratio of HTML-based text to images. A low text-to-image ratio (many images) has historically been linked with spam emails.

Throttling – the tactic of sending out your emails on a single campaign over a period of time, usually a few hours. Throttling means your emails will not get sent to your target list all at once, which can be good for your deliverability.

Touchpoint – a marketing point of contact with your subscriber. A touchpoint refers to any time your brand is in contact with your subscribers through your marketing efforts. Your contact receiving an email would represent a touchpoint.

Transactional Emails – non-commercially focused emails. These include order confirmations, shipping confirmations, and password reset emails. Transactional emails can be sent to users regardless of opt-out status. These emails should not focus on driving contacts to buy, and a general rule of thumb for transactional emails is at least 80% of the content should be focused on the transaction.

Triggered Email – see Autoresponder.


Unicode Characters – these “special” characters are unicode symbols such as hearts, stars, and snowflakes. Email marketers use these characters in subject lines to give a visual element and attempt to stand out in the email inbox.

Unsubscribe – the action a subscriber takes when he or she no longer wishes to be sent your marketing emails. You have 10 days to honor unsubscribe requests to be compliant with CAN-SPAM law.


Webmail – a web-based email client used to view email. Gmail, Yahoo!, and Hotmail all have webmail that provides web browser based interfaces.

Whitelisting – the process of indicating specifically that an email sender’s mail is wanted. Usually, the process of whitelisting involves adding a contact to your email address book. Future mail from this contact will always be delivered to your inbox, by passing any spam filters.

Win-Back – see Re-Engagement Campaign.

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