SEO and PPC glossary
Plain-English definitions of the search marketing terms you will meet: from alt text and canonical tags to click fraud, Core Web Vitals and Site Strength.
A
Alt text
A short description of an image in its alt attribute. Read aloud by screen readers and used by search engines to understand the image.
Anchor text
The clickable words of a link. Descriptive anchor text ("boiler servicing prices") tells people and search engines what the linked page is about.
B
Backlink
A link from another website to yours. Also called an inbound link. See links and authority.
C
Canonical tag
A tag naming the main address of a page when the same content is reachable at several addresses, so search engines index one version.
Citation
A mention of a business's name, address and phone number on another website, such as a directory. Important for local SEO.
Click fraud
Clicks on paid ads made with no intention of buying, by competitors, bots or paid clickers. See click fraud in Google Ads.
Click-through rate (CTR)
The share of people who saw a result or ad and clicked it. Clicks divided by impressions.
Core Web Vitals
Google's measures of real visitors' experience: Largest Contentful Paint (loading), Interaction to Next Paint (responsiveness) and Cumulative Layout Shift (visual stability).
Crawl budget
How many pages a search engine is willing to crawl on a site in a given time. Mostly a concern for large sites, or sites wasting crawls on errors and duplicate pages.
Crawler
A program that fetches web pages and follows their links. Search engines and AI assistants both run crawlers. Also called a bot or spider.
D
F
Featured snippet
An answer shown in a box at the top of search results, quoted from a web page.
G
Google Business Profile
The free listing that shows a business in Google Maps and the local pack, with its address, hours, photos and reviews.
H
Harmonic centrality
A measure of how close a site is to every other site on the web through links. Used by Common Crawl to rank domains, and the basis of Site Strength.
I
Impression
One showing of a search result or ad to a searcher, whether or not it was clicked.
Indexing
A search engine storing a page so it can appear in results. A page can be crawled and still not indexed.
Internal link
A link from one page of a site to another page of the same site.
Invalid click
Google's term for clicks it considers not genuine, such as accidental double clicks and known bots. Invalid clicks it detects are not charged.
J
JSON-LD
The format Google recommends for structured data: a block of JSON inside a script tag in the page.
K
Keyword
A word or phrase people type into a search engine. Also called a search term or query.
Keyword difficulty
An estimate of how hard it would be to rank on page one for a keyword, based on how strong the pages already ranking are.
L
Landing page
The page a visitor arrives on from a search result or an ad.
Local pack
The map and three business listings shown for searches with local intent, such as "plumber near me".
Long-tail keyword
A longer, more specific search phrase, such as "emergency boiler repair Headingley". Fewer searches each, but usually clearer intent and less competition.
M
Meta description
The short summary of a page shown under its title in search results. It influences clicks rather than rankings.
N
NAP
Name, address and phone number. Consistent NAP across the web helps local rankings.
Negative keyword
A word added to a Google Ads campaign to stop ads showing for searches containing it, such as "jobs" or "free".
Nofollow
A link attribute (rel="nofollow", sponsored or ugc) asking search engines not to treat the link as an endorsement.
Noindex
A tag asking search engines not to include a page in results.
O
Organic traffic
Visitors who arrive from unpaid search results.
Orphan page
A page no other page on the site links to. Crawlers may never find it.
P
PPC
Pay-per-click advertising, where the advertiser pays each time an ad is clicked. Google Ads is the best-known example.
R
Redirect
An instruction sending visitors and crawlers from one address to another. A 301 is permanent; a 302 is temporary.
Robots.txt
A text file at the root of a site telling crawlers which parts they may fetch.
S
Schema markup
Another name for structured data using the schema.org vocabulary.
SERP
Search engine results page: everything shown after a search, including ads, maps, snippets and ordinary results.
Site Strength
Our 0 to 100 estimate of how well linked a domain is, calculated from Common Crawl's public web graph. See how Site Strength works.
Sitemap
An XML file listing the pages a site wants search engines to find.
Spam signals
Traits that low-quality or spam sites tend to share, such as a very new domain, hundreds of outbound links or no contact details. Worth a look together; any one alone is normal.
Structured data
Code that states facts about a page (business details, products, reviews, events) in a form search engines read reliably.
T
Title tag
The HTML title of a page, shown as the clickable headline in search results.
V
Visibility
A score combining the rankings of all tracked keywords, weighted by how many clicks each position typically earns.