Definitions beginning with E

E-commerce

Online sale of products or services with catalogue, ordering, payment and transaction tracking.

In practice: test a complete order, payment errors and post-purchase support.

E-E-A-T

Experience, Expertise, Authoritativeness and Trustworthiness: a framework in Google quality guidance, not a single SEO score.

In practice: show who owns the content, how it was produced and what evidence supports it.

Edge computing

Data processing performed close to the user or source rather than in a single central facility.

In practice: Add edge processing only when a latency or location need has been measured.

Email bounce

Email delivery-failure signal. Temporary or permanent interpretation depends on the returned code and context; absence of a bounce does not prove reading.

Reference: Google : Email sender guidelines

Test an invalid destination and check that failure reaches its owner without endless retries.

Email deliverability

Practical ability of a sent message to reach the intended inbox and remain readable.

In practice: test arrival in several real inboxes.

Email marketing

Use of permission-based email to inform, retain, support or convert an audience.

In practice: check contact provenance, message usefulness and unsubscribe flow before sending.

Email subject

Email subject line identifying the action or request without exposing sensitive details.

In practice: name the request without private details in the subject.

Embedding

Numerical representation of text, images or data in vector space to compare semantic similarity.

In practice: test retrieval on relevant documents and similar but distinct questions.

Encryption

Reversible transformation making data unreadable without the appropriate key. Protection depends on the algorithm, implementation and key management. It differs from hashing; losing keys can prevent recovery of data even when backups exist.

Reference: OWASP : Cryptographic Storage · Source consulted 2026-10-18

In practice: distinguish data in transit from stored data, then check where each needs protection.

Endpoint

API access point for a particular operation. Address, method and parameters form a usage to document; two methods at one address can have different effects.

Source consulted : MDN · 2026-10-17

In practice: Document format, error states and usage limits for each public endpoint.

Engagement rate

Engagement rate: proportion of users or sessions meeting interaction criteria defined by a platform.

In practice: Read the tool’s definition and compare it with a genuinely useful action.

Enquiry acknowledgement

Message confirming that a system or team received an enquiry. It should state what happens next without being confused with a substantive reply or proof that every internal notification arrived.

In practice: compare the visitor confirmation with the enquiry actually received by the team.

Enquiry owner

Person or team responsible for following an enquiry, obtaining needed details, replying and recording why it is closed.

In practice: assign an owner and fallback to each enquiry type.

Entity

A person, place, organization, product or concept that can be distinctly identified and connected to other information.

In practice: Keep the organisation’s name, activity and official links consistent across its profile pages.

Entity home

Reference page chosen to present an organization, person or brand identity, attributes and relationships consistently.

In practice: Choose a public reference page that clearly describes the entity and its verifiable links.

Entity salience

Relative importance of an entity within text or data, estimated from its context, mentions and relationships.

In practice: Clarify the main subject through title, facts and contextual links without repeating a name artificially.

Error 404

HTTP response indicating that the requested resource was not found. It does not itself distinguish temporary from permanent absence; a useful page can offer recovery paths.

Source consulted : MDN · 2026-10-17

In practice: check the cause, internal links and best next step for an old URL.

Error budget

Allowance for unavailability or errors derived from a reliability objective and used to balance change with stabilization.

In practice: define which incidents consume the budget and what decision follows exhaustion.

Error summary

Overall feedback gathering form validation errors and helping users locate affected fields. It complements local messages; check its location and navigation with a keyboard.

Reference: W3C : Error identification · Source consulted 2026-10-18

In practice: announce errors near the start of the form after submission.

ETag

Identifier for a version of an HTTP representation, usable to compare a known response with the current version. It need not be a hash or modification date.

Reference: MDN : ETag

Source consulted : MDN · 2026-10-17

Compare responses for an unchanged and then changed document; inspect the validator at each step.

European Accessibility Act

European framework imposing accessibility requirements on certain products and services, with scope depending on activity and context.

In practice: Check the service, territory and applicable official texts before planning compliance.

Event page

Page for a specific gathering with date, times, place or online access, agenda and registration state.

In practice: verify date, times, place and registration on a phone before publishing.

Event recap

Summary published after a gathering to preserve the topics covered and resources actually shared.

In practice: promise only materials and recordings that are actually available.

Event status

Indication of an event’s current state, such as open, full, postponed, cancelled or completed.

In practice: update the action and page as soon as registration closes or the date changes.

Event time zone

Time-zone reference attached to an event date so attendees elsewhere interpret the stated time correctly.

In practice: show the time zone when attendees may be in different locations.

Event tracking

Recording defined journey events, such as clicks, submissions or confirmations. Name each stage precisely: sending analytics or counting a click does not establish that the business operation succeeded.

Reference: MDN : Sending analytics data · Source consulted 2026-10-18

In practice: test each event on the real page, including failed and repeated actions.

Event-driven architecture

Architecture in which components produce and consume events to trigger decoupled processing.

In practice: Document producer, consumer and handling of repeated or missing events.

Evergreen content

Content addressing a need that remains useful beyond a single news event, such as understanding a process or choosing a method. Lasting usefulness does not mean immutability: references, examples and conditions can age. It depends on fact- and need-driven reviews rather than merely changing the displayed date.

Reference: Google Search Central : Helpful content · Source consulted 2026-10-18

In practice: review a guide against readers’ current questions. Correct outdated steps and remove obsolete references; retain the address when the need stays the same and indicate a revision only when content has actually changed.

Exact match domain

Domain name closely or exactly matching a target query. It does not by itself guarantee strong rankings.

In practice: Choose a durable brand domain and check practical use before prioritising a keyword.

Exceptional opening hours

Dated change to normal opening or reception hours, such as a closure or extended day.

In practice: date the closure and update external copies of opening hours.

EXIF

Photo file metadata that can describe capture details, orientation and information added by an editor; it does not replace alt text.

In practice: Review location or device metadata before publishing a photograph.

Exit cost

Work and expense needed to recover data, replace a supplier, transfer access and continue a service without undue disruption.

In practice: run a test export and estimate who would transfer content, domain, data and functions if the supplier changes.

Extranet

Private area accessible to authorized partners, customers or members from outside an organization.

In practice: Define groups, documents and needed rights before opening a private space.