Digital visibility glossary

47 terms from search, performance, technical infrastructure, structured data and artificial intelligence. Every definition is 25–45 words, stands on its own, and has its own anchor.

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Last updated: 15 September 20265 categories · 47 termsQuoting allowed, with attribution

How should you use this glossary?

Answer

This glossary is not written to be read end to end. Keep it open while you read a proposal or a technical report, and find the term from the category index or the alphabetical index. Every term has its own anchor address, which you can share directly. Definitions run 25–45 words and hold their meaning out of context.

The problem corporate teams run into is not that the terms are difficult. It is that the same term means something different in every proposal. If one agency uses “SEO” to mean content writing only and another uses it to mean a technical audit only, the two scopes cannot be compared. This glossary exists to build the shared language that makes comparison possible: each term is defined in one sense, and the definition is the same sentence as the DefinedTerm markup in this page’s structured data.

Most of the terms are not sufficient on their own; they take their meaning together. After you read one, follow the anchors on the “see also” line. If you want the full subject, the guide or service link under each definition goes to the page that shows where the term sits in practice. Which terms are read together is written in the term clusters section.

You may quote these definitions with attribution; the conditions are written in the terms of use. AI crawlers are also explicitly allowed to read and quote this page: the relevant crawlers are listed line by line as Allow in our robots.txt file.

Where do the numbers in these definitions come from?

Every threshold value in this glossary is taken from public primary documentation. No estimate, no rounding, no figure passed on second hand. The table below collects all of the thresholds used in the performance terms, each with its source.

Threshold values used in this glossary · Source: Google web.dev · Accessed: 2026-07-29
Metric	What it measures	Good threshold	Source
LCP	Time until the largest content element in the viewport is painted	2.5 s	web.dev — LCP
INP	Delay before a visible response is painted after an interaction	200 ms	web.dev — INP
CLS	Total unexpected layout movement during load	0.1	web.dev — CLS
TTFB	Interval between sending the request and receiving the first byte	0.8 s	web.dev — TTFB

2.5 s

The published good threshold for Largest Contentful Paint. Like every number on this page it is given with its source and the date it was accessed; a value whose source cannot be shown is not published here.

Source: Google web.dev — Largest Contentful Paint (LCP) · Accessed: 2026-07-29

Which categories do the terms fall into?

Answer

There are five categories: Search, Performance, Technical, Structured Data and Artificial Intelligence. The split follows responsibility rather than subject, because in a corporate project each category is a different team’s work. The category indexes are below; the full definitions are in the alphabetical list.

Five categories · What each one answers, how many terms it holds, which resource it links to
Category	What it answers	Terms	Related resource
Search	How do people and engines find my page, and where is it shown?	10	AEO guide
Performance	How fast and how stable is the page, and who measures it with what data?	13	Core Web Vitals guide
Technical	Is the infrastructure crawlable, multilingual and accessible?	13	Corporate website
Structured Data	Where does a machine learn what my company is?	7	Schema.org guide
Artificial Intelligence	Do language models reach my page, and do they cite it in the answer?	4	GEO guide

Search — where and how your page is shown

Terms that separate ranking, answer boxes and generated summaries. When a proposal uses the word “visibility”, these terms tell you which layer is actually being discussed.

AEO
E-E-A-T
Extractable passage
GEO
Local pack
Multi-location SEO
NAP
Rich result
SEO
SERP

Performance — speed, stability and the source of the measurement

The Core Web Vitals metrics and the data they are measured with. The distinction between field data and lab data settles most of the arguments a performance report produces.

CLS
Core Web Vitals
Critical rendering path
CrUX
FID
Field data
INP
Lab data
LCP
Lighthouse
Performance budget
TBT
TTFB

Technical — crawlability, multiple languages, accessibility

Terms that describe the infrastructure. A fault in this layer limits the result of every other piece of work, however good the content and the design are.

Alt text
canonical
Crawl budget
Crawler
Headless CMS
hreflang
Index
robots.txt
Static site
Visible focus indicator
WCAG
WCAG 2.1 AA
x-default

Structured Data — how a machine learns what your company is

The markup terms that let a machine read the page without guessing. Until this layer exists, being recognised as the right entity by an AI engine is left to chance.

DefinedTerm
Entity
JSON-LD
Knowledge graph
sameAs
schema.org
Structured data

Artificial Intelligence — access permission and citation

Terms that describe how language models reach your pages and how they cite sources in an answer. The decisions in this category are corporate policy rather than technical detail.

AI crawler
AI Overviews
LLM
llms.txt

47 terms, in alphabetical order

Answer

The list below is ordered A to Z. Each entry carries its category next to the term, the anchors of related terms under the definition, and a link to the page that shows the term in practice. Abbreviations are given with their full form, and every definition containing a number carries a source and access date.

Terms beginning with A

AEOSearch

AEO (Answer Engine Optimization) is the work of making a page directly quotable inside search answer boxes and AI assistants. SEO targets ranking; AEO targets being the source of the answer. Success is measured in citations, not clicks.

Terms beginning with C

canonicalTechnical

canonical is the link tag that tells a search engine which address is the primary version when the same or near-identical content exists at several URLs. Set incorrectly, ranking signals accumulate on the wrong address and two versions compete with each other.

Terms beginning with D

DefinedTermStructured Data

DefinedTerm is the schema.org type that declares a term's definition to machines. Terms are collected under a DefinedTermSet. Every definition on this page is marked up as a DefinedTerm, and the sentence in the markup is identical to the visible one.

Source pageSchema.org guide: choosing the right type

↑ Back to the alphabetical index

Terms beginning with E

E-E-A-TSearch

E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness, the criteria in Google's public quality rater guidelines. It is not a score inside the ranking system; it describes signals such as a named author, verifiable identity and consistent corporate data.

Terms beginning with F

FIDPerformance

FID (First Input Delay) was the Core Web Vitals responsiveness metric until March 2024, when INP replaced it. FID measured only the delay before the first interaction was processed; INP measures the full response time across all interactions in a visit.

Terms beginning with G

GEOSearch

GEO (Generative Engine Optimization) is the work of making a brand citable inside answers produced by generative engines such as ChatGPT, Claude, Perplexity, Gemini and AI Overviews. It rests on machine readability and entity clarity rather than on link authority.

Terms beginning with H

Headless CMSTechnical

A headless CMS stores and edits content but does not render the pages; the front end fetches the content over an API or at build time. The editing experience stays, while performance and security stop depending on the content system.

Source pageCorporate website: the technology decision

hreflangTechnical

hreflang is the tag that tells a search engine which language and region version of a page to show. Every version must point back at every other, including itself; a one-way declaration is ignored and the wrong language is served.

Terms beginning with I

IndexTechnical

The index is the database in which a search engine stores crawled pages and matches them against queries. Being crawled does not mean being indexed: a page-level robots meta tag, thin content or duplicate versions can keep a page out.

Terms beginning with J

JSON-LDStructured Data

JSON-LD is the JSON-based format for writing structured data inside a script tag, separately from the visible markup. Google recommends it because content and markup do not tangle, and a page's whole entity graph can live in a single block.

Source pageStructured data and schema service

↑ Back to the alphabetical index

Terms beginning with K

Knowledge graphStructured Data

A knowledge graph is the data structure in which a search engine stores entities and the relationships between them. If your company is a defined node in that graph, the engine knows who is meant when your name appears; otherwise it guesses each time.

Terms beginning with L

Lab dataPerformance

Lab data is performance measured in a controlled environment with a fixed device profile and a throttled network, which is what Lighthouse produces. It is repeatable and good for diagnosis, but it is not the data Google uses to assess Core Web Vitals.

Terms beginning with M

Multi-location SEOSearch

Multi-location SEO is the work that makes one brand visible separately for each branch, dealer or service area. Every location gets its own page, its own NAP data and its own LocalBusiness markup; a single list page does not do the same job.

Terms beginning with N

NAPSearch

NAP stands for name, address and phone number, the identity triple a business publishes. It has to read identically on the site, in structured data and in every business profile; a mismatch splits one company into several in the engine's view.

Source pageCorporate web design agency in Kocaeli, Turkey

↑ Back to the alphabetical index

Terms beginning with P

Performance budgetPerformance

A performance budget is a written ceiling on page weight, request count and metric values that a project agrees not to exceed. It turns performance from an opinion into an acceptance criterion, and a build that breaks the ceiling fails before release.

Source pagePerformance optimisation: acceptance criteria

↑ Back to the alphabetical index

Terms beginning with R

Rich resultSearch

A rich result is a search listing displayed with extra elements such as review stars, FAQ lines, breadcrumbs or prices, drawn from structured data. Valid markup makes a page eligible; it does not guarantee display, because the engine decides per query.

Terms beginning with S

sameAsStructured Data

sameAs is the structured data property that links an entity to its other verifiable addresses: social profiles, registry records, professional directories. It is how an engine confirms that the company on your site and the one in another database are the same organisation.

Source pageSchema.org guide: linking entities

schema.orgStructured Data

schema.org is the shared vocabulary that defines the types and properties used in structured data: Organization, Product, FAQPage, DefinedTerm and several hundred more. Search engines and generative engines read the same vocabulary, so one markup layer serves both.

Terms beginning with T

TBTPerformance

TBT (Total Blocking Time) is the lab metric that totals the time the main thread was blocked by long tasks during load. Lighthouse reports it as a proxy for responsiveness, because INP needs a real interaction and cannot be measured in a simulation.

Terms beginning with V

Visible focus indicatorTechnical

A visible focus indicator is the outline that shows which element currently has keyboard focus. Removing it without a replacement makes a page unusable for keyboard and screen reader users; it is checked directly in a WCAG 2.1 AA conformance review.

Terms beginning with W

WCAGTechnical

WCAG (Web Content Accessibility Guidelines) is the W3C standard that defines how web content is made usable by people with disabilities. It is organised around four principles, perceivable, operable, understandable and robust, and three conformance levels: A, AA and AAA.

Source pageDigital asset audit: the accessibility axis

WCAG 2.1 AATechnical

WCAG 2.1 level AA is the middle conformance level of the standard and the one this site is built to. It requires, among other things, a contrast ratio of at least 4.5:1 for normal text, full keyboard operability and a visible focus indicator.

SourceW3C — WCAG 2.1, Contrast (Minimum)Accessed: 2026-07-29

Source pageCorporate website: the accessibility report

↑ Back to the alphabetical index

Terms beginning with X

x-defaultTechnical

x-default is the hreflang value that names the page to serve when no language or region version matches the visitor. Without it the engine picks one itself, which for a multi-market site usually means the wrong market gets the wrong page.

Source pageExport industry: language and market architecture

↑ Back to the alphabetical index

Which terms should be read together?

Answer

The terms take their meaning in five clusters rather than one by one: visibility layers, speed and stability, machine readability, AI access, and multilingual or multi-location structure. If one term from a cluster is on the agenda of a meeting, the rest of that cluster is too, which is why they are listed separately.

Each cluster can be worked on separately. In practice, though, a gap in one limits the result of the work done in another: a page that cannot be crawled cannot be quoted, and a company that is not recognised as an entity cannot be cited as a source in a generative answer. Setting the order and the priorities is what an audit is for.

To see the measurable checks behind these clusters on your own site, request the digital asset audit: it assesses five axes in one report. On multilingual sites only the primary-language version is measured; mapping between language versions and location structure is not assessed separately. Which service each term corresponds to in practice is written in the service scope matrix.

Frequently asked questions about this glossary

May I quote these definitions?

Yes. You may quote the definitions with attribution and a link back to this page; the conditions are written on the terms of use page. Every term has its own anchor address, so you can link straight to a single definition. AI crawlers are also explicitly allowed to read and quote this page.

Why are the definitions so short?

Each definition is kept between 25 and 45 words, because a passage of that length keeps its meaning when it is lifted out of its context. It carries as it is into an email, a meeting note or an assistant answer. Subjects that need a longer treatment live in the knowledge centre guides, not here.

Are SEO, AEO and GEO different names for the same thing?

No. SEO targets ranking on the search results page, AEO targets being quoted in answer boxes and assistants, and GEO targets being cited inside the answer a generative engine writes. The three are judged by different measures and need different work, but the upper layer does not hold without the one beneath it.

The term I need is not here. What should I do?

Write to bilgi@bakibilisim.com; we add the term and change the update date of the page. The same address applies to corrections: if you think a definition is wrong or a threshold has moved, tell us. This page is an open reference rather than part of a product, and its errors are corrected in the open.

How often is the glossary updated?

The last updated date at the top of the page is identical to the dateModified field in the structured data. When the public documentation we cite changes, or a term is added, the content is updated and the date changes that day. If nothing changed, the date does not change either; we do not refresh dates to make a page look recent.

Let us measure how these terms apply to your own site.

Several headings in this glossary are measurable: which crawlers your robots.txt allows, whether your pages have a single h1 and question-form headings, whether your structured data is valid, and where your lab-measured Core Web Vitals sit against the published thresholds. The free digital asset audit measures these, together with an automated accessibility scan, and returns a report within five working days.

Free Digital Asset Audit Book a Discovery Call

The audit is free and creates no obligation to work with us. We work with corporate-scale, multi-location or multilingual organisations; one-off small jobs fall outside our scope, and in that case we point you to smaller studios.

Digital visibility glossary

How should you use this glossary?

Where do the numbers in these definitions come from?

Which categories do the terms fall into?

Search — where and how your page is shown

Performance — speed, stability and the source of the measurement

Technical — crawlability, multiple languages, accessibility

Structured Data — how a machine learns what your company is

Artificial Intelligence — access permission and citation

47 terms, in alphabetical order

ATerms beginning with A

CTerms beginning with C

DTerms beginning with D

ETerms beginning with E

FTerms beginning with F

GTerms beginning with G

HTerms beginning with H

ITerms beginning with I

JTerms beginning with J

KTerms beginning with K

LTerms beginning with L

MTerms beginning with M

NTerms beginning with N

PTerms beginning with P

RTerms beginning with R

STerms beginning with S

TTerms beginning with T

VTerms beginning with V

WTerms beginning with W

XTerms beginning with X

Which terms should be read together?

Frequently asked questions about this glossary

Let us measure how these terms apply to your own site.

Terms beginning with A

Terms beginning with C

Terms beginning with D

Terms beginning with E

Terms beginning with F

Terms beginning with G

Terms beginning with H

Terms beginning with I

Terms beginning with J

Terms beginning with K

Terms beginning with L

Terms beginning with M

Terms beginning with N

Terms beginning with P

Terms beginning with R

Terms beginning with S

Terms beginning with T

Terms beginning with V

Terms beginning with W

Terms beginning with X