The SEO glossary for buyers
Short, sourced definitions of the terms that come up when you buy search work: SEO, GEO and AI search, conversion rate optimization, analytics and the platforms your site runs on. Each entry opens on a plain answer, says why it matters to you, and links to the deeper guide.
30 minutes. No pitch deck. You leave with a prioritised plan.
Search has picked up a second vocabulary in two years. The old one, rankings, backlinks, Core Web Vitals, never went away, and a new one arrived on top of it: AI Overviews, AI Mode, query fan-out, citations, GEO. Proposals mix the two freely, and it is hard to judge a plan when half of its nouns are unfamiliar.
This glossary is the reference we wish buyers had before a sales call. Every entry opens on a definition short enough to read in one breath, then says two things a generic dictionary does not: why the term should matter to someone paying for the work, and how it is actually measured or applied. Where a claim rests on a search engine's documentation or a piece of research, the source is listed at the foot of the entry.
How is the glossary organised?
Alphabetically, with a filter for five areas: SEO, GEO and AI search, conversion rate optimization, analytics, and the platforms sites are built on. Terms link to their neighbours, so an entry on AI Overviews points on to query fan-out and zero-click searches, and each one links down to the longer guide on the blog when that guide is live.
What will you not find here?
Invented numbers. Where a figure appears it comes from the named source. We also leave out jargon that exists only to sell a tool, and we say plainly when a term is overhyped, as the entry on llms.txt does.
A
- A/B test
- An A/B test is an experiment that splits visitors at random between two versions of a page or element, the original and a variation, and compares how each performs on one chosen goal, such as sign-ups or purchases, to find out whether the change caused a real difference or just random variation.
- Above the fold
- Above the fold is the part of a webpage visible on screen before a visitor scrolls, named after the fold on a physical newspaper.
- Average order value (AOV)
- Average order value is the average amount spent each time a customer places an order, calculated by dividing total revenue by the number of orders over a period.
C
- Call to action (CTA)
- A call to action is the specific instruction, usually a button or a short line of text, that tells a visitor exactly what to do next, such as "Book a free audit" or "Start free trial." It is the point where a page converts interest into a measurable action.
- Cart abandonment rate
- Cart abandonment rate is the share of shopping carts that are started but never completed as a purchase, calculated as one minus completed transactions divided by carts created.
- Conversion funnel
- A conversion funnel is the sequence of steps a visitor moves through on the way to a goal, such as landing page, product page, cart, checkout, confirmation, with a smaller number of people completing each successive step.
- Conversion rate
- Conversion rate is the percentage of visitors who complete a defined goal, such as a purchase, a form submission or a booked call, out of total visitors in a given period.
- Conversion rate optimization (CRO)
- Conversion rate optimization (CRO) is the practice of increasing the share of website visitors who take a desired action, such as booking a call, submitting a form or completing a purchase, by finding what stops them and testing changes to pages, forms and checkout flows.
H
- Heatmap
- A heatmap is a visual overlay on a page showing where visitors click, move their cursor, or how far down they scroll, aggregated across many sessions and shown as a colour gradient from cool to hot.
L
- Landing page
- A landing page is a standalone page a visitor arrives at from a specific source, such as an ad, an email or a search result, built around a single, focused goal rather than general site navigation.
M
- Minimum detectable effect (MDE)
- The minimum detectable effect is the smallest improvement in a metric, such as conversion rate, that an A/B test is designed to reliably detect given its sample size and duration.
- Multivariate testing
- Multivariate testing is an experiment that tests multiple page elements, such as a headline, an image and a button colour, in combination at once, measuring not just each element's individual effect but how they interact.
S
- Sample ratio mismatch (SRM)
- Sample ratio mismatch is a data-quality problem in an A/B test where the actual split of visitors between variants differs from the intended split, such as a planned fifty-fifty split landing at fifty-six to forty-four, by more than chance would explain.
- Session recording
- A session recording is a replay of an individual visitor's actual interactions on a page, mouse movement, clicks, scrolling and typing, reconstructed from captured browser events rather than a video recording.
- Social proof
- Social proof is evidence that other real people or businesses have used and trust a product or service, shown through testimonials, client logos, review scores, case studies or usage numbers.
- Statistical significance
- Statistical significance is a measure of how likely it is that a difference observed in a test, such as one page version converting better than another, is a real effect rather than random chance.
T
- Test hypothesis
- A test hypothesis is a written, specific statement of what will be changed, why it is expected to help based on evidence, and what metric will show whether it worked, written before an A/B test begins.
V
- Value proposition
- A value proposition is a clear statement of the specific outcome a product or service delivers, for whom, and why it is a better choice than the alternatives.
Questions we get asked
Who writes these definitions?
The two founders, Ibrahem Helal and Jeremy Zava, write and review every entry. Each one names at least one source you can check, usually the search engine's own documentation or the original research, so you are not taking a definition on our word alone.
Why does every entry open with a short paragraph?
Because that paragraph is the answer. It is written to make sense on its own in forty to sixty words, which is also the shape search features and AI assistants quote. The rest of the entry says why the term matters to a buyer and how it is measured or applied.
What is the difference between SEO, GEO and AEO?
SEO gets pages ranked in search results. GEO gets a brand named and cited in answers from assistants such as ChatGPT, Perplexity, Claude and Google's AI features. AEO is the older label for structuring answers so search features can lift them. The work overlaps heavily, and each has its own entry here.
How often are new terms added?
Two a day from 24 September 2026 until the planned list of 120 terms is complete, then as new terms enter common use. Entries are updated when the underlying documentation changes, and the date on each entry says when that last happened.
Can I quote or link to a definition?
Yes. Link to the entry's own page so readers get the source list with it. If a definition is wrong or out of date, email us and we will correct it and change the date on the entry.
Do you sell every service described here?
No. The glossary covers terms buyers meet whoever they hire. Where we do the work, the entry links to the service page; where we do not, it says what the term means and stops there.
Thirty minutes to see where your site is invisible.
Book a free consultation with Ibrahem and Jeremy. We look at your site on search, AI answers and conversion while we talk, and you leave with a prioritised plan.
30 minutes. No pitch deck. You leave with a prioritised plan.