SEO Glossary: 60 SEO Terms Explained in Plain English
Every SEO term you are likely to hear from an agency or see in a report, explained in simple language with why it matters for your business.
- 60 terms
- Written for business owners
- No jargon
This SEO glossary explains 60 common search engine optimization terms in plain language, from 301 redirects and backlinks to SERP, schema markup and zero-click searches. Use the letters below to jump to any term.
SEO comes with a lot of jargon. When an agency talks about canonical tags, referring domains or search intent, it is easy to nod along without knowing whether the work matters for your business. This glossary explains the terms you are most likely to hear, without the technical fog.
Each definition is written for business owners rather than developers, and many include a short note on why the term matters in practice. We use this list ourselves when we explain monthly reports to MarketingFlow clients, and it reflects what we have learned over 9 years and more than 1,500 campaigns.
A to Z
SEO terms from A to Z
0-93 terms
- 301 redirect
- A permanent redirect that sends visitors and search engines from an old URL to a new one. It passes most of the old page's ranking value to the new page, which makes it the right choice when you move or rename a page.
- 302 redirect
- A temporary redirect. It tells search engines the move is short-term, so they usually keep the original URL in results. Use it only when the old page will come back.
- 404 error
- The status code a server returns when a page cannot be found. A few 404s are normal, but broken links to important pages waste visits and should be fixed or redirected.
A3 terms
- Algorithm
- The set of rules and systems a search engine uses to decide which pages to show and in what order. Google updates its algorithms many times a year.
- Alt text
- A short text description added to an image in the HTML. It helps people using screen readers and helps search engines understand what the image shows.
- Anchor text
- The clickable words in a link. Natural anchor text, such as your brand name or a short description, is safer than repeating the same keyword in every link.
B3 terms
- Backlink
- A link from another website to yours. Backlinks from relevant, trusted websites are one of the strongest signals search engines use to judge authority.
- Black hat SEO
- Tactics that try to trick search engines and break their guidelines, such as buying spam links, hiding text or stuffing keywords. They can lead to penalties.
- Breadcrumbs
- A small trail of links, like Home > Services > Local SEO, that shows where a page sits on a website. They help visitors navigate and help search engines understand site structure.
C6 terms
- Canonical tag
- A tag in a page's HTML that tells search engines which URL is the main version of a page. It prevents duplicate versions from splitting ranking signals.
- Citation
- An online mention of your business name, address and phone number, usually in a directory. Consistent citations help local rankings.
- Click-through rate (CTR)
- The percentage of people who click your result after seeing it. If 1,000 people see your page in search and 50 click, your CTR is 5%.
- Core Web Vitals
- Google's measurements of real-world page experience: how fast the main content loads, how quickly the page responds to input and how stable the layout is while loading.
- Crawl budget
- The number of pages a search engine is willing to crawl on your site in a given time. It mainly matters for large sites with thousands of pages.
- Crawling
- The process of search engine bots visiting web pages and following links to discover new and updated content.
D2 terms
- Domain Rating (DR)
- An Ahrefs metric from 0 to 100 that estimates the strength of a website's backlink profile. Google does not use it, but it is useful for comparing sites. Check yours with our free DR checker.
- Duplicate content
- The same or very similar content appearing at more than one URL. It can make search engines unsure which version to rank.
E1 term
- E-E-A-T
- Short for Experience, Expertise, Authoritativeness and Trustworthiness. Google's quality guidelines use it to describe what makes content reliable, especially on topics that affect money or health.
F1 term
- Featured snippet
- A highlighted answer shown near the top of some Google results, taken from a web page. Clear, direct answers to questions have the best chance of being chosen.
G3 terms
- Google AI Overviews
- AI-generated summaries that appear at the top of some Google searches, with links to the sources used. Pages that rank well and answer questions clearly are more likely to be cited.
- Google Business Profile
- Google's free business listing that appears on Google Maps and in local results. A complete, accurate profile is the foundation of local SEO. See our Google Business Profile optimization service.
- Google Search Console
- A free Google tool that shows which searches your site appears for, how many clicks you get, which pages are indexed and any problems Google finds.
H2 terms
- Heading tags (H1 to H6)
- HTML tags that mark the headings on a page. Each page should have one H1 describing the page, with H2 and H3 headings for sections.
- Hreflang
- A tag that tells search engines which language or regional version of a page to show. Useful for sites with English and French versions.
I3 terms
- Impressions
- The number of times your page appeared in search results, whether or not anyone clicked it.
- Indexing
- The process of a search engine storing a page in its database so it can appear in results. A page that is not indexed cannot rank.
- Internal link
- A link from one page on your website to another page on the same website. Internal links help visitors find related pages and spread authority across your site.
K3 terms
- Keyword
- A word or phrase people type into a search engine. Good SEO plans each page around a clear group of keywords. Learn how in our keyword research guide.
- Keyword cannibalization
- When two or more pages on the same site target the same keyword and compete with each other, often making both rank lower.
- Keyword difficulty
- An estimate of how hard it is to rank for a keyword, usually based on the strength of the pages already ranking. Each tool calculates it differently.
L4 terms
- Link building
- The work of earning backlinks from other websites, usually through outreach, partnerships and content worth referencing.
- Local pack
- The group of business listings, usually three, shown with a map for local searches like "dentist near me". It is also called the map pack.
- Local SEO
- Optimizing a business to appear in local searches and on Google Maps, through its Google Business Profile, location pages, citations and local links. Learn more about our local SEO services.
- Long-tail keyword
- A longer, more specific search phrase, such as "emergency furnace repair in Barrhaven". Each one has fewer searches but usually less competition and clearer intent.
M2 terms
- Meta description
- A short summary of a page in its HTML, often shown under the title in search results. It does not directly affect rankings but strongly affects clicks.
- Mobile-first indexing
- Google mainly uses the mobile version of a page for indexing and ranking, so your site must work well on phones.
N3 terms
- NAP
- Short for Name, Address and Phone number. Keeping your NAP identical on your website and every listing is a basic local SEO task.
- Nofollow
- A link attribute that tells search engines not to pass ranking credit through a link. Google treats it as a hint rather than a strict rule.
- Noindex
- A tag that tells search engines not to include a page in their results. Useful for thank-you pages and private pages, harmful if left on important pages by mistake.
O3 terms
- Off-page SEO
- Everything done outside your own website to improve rankings, mainly earning backlinks, mentions and citations.
- On-page SEO
- Optimizing the content and HTML of your own pages, including titles, headings, content, images and internal links.
- Organic traffic
- Visitors who arrive from unpaid search results, as opposed to ads, social media or email.
P3 terms
- PageRank
- Google's original system for measuring the importance of pages based on the links pointing to them. It is still part of how Google evaluates links, though no longer shown publicly.
- Page speed
- How quickly a page loads and becomes usable. Faster pages keep more visitors and support better rankings, especially on mobile.
- People Also Ask
- A box in Google results that shows related questions with short answers. It is a useful source of content ideas.
R3 terms
- Referring domain
- A unique website that links to yours. Ten links from one site count as one referring domain, which is why variety matters.
- Rich results
- Search results with extra visual features, such as breadcrumbs, prices or images, often made possible by structured data.
- Robots.txt
- A file at the root of a website that tells crawlers which areas they may or may not visit. A wrong rule can block important pages.
S6 terms
- Schema markup
- Code added to a page, usually in JSON-LD format, that describes its content in a standard way so search engines understand it. Also called structured data.
- Search intent
- The goal behind a search: learning something, finding a specific website, comparing options or buying. Pages rank best when they match the intent.
- SERP
- Short for Search Engine Results Page, the page you see after searching. A modern SERP can include ads, maps, AI answers, videos and regular results.
- Service area business
- A business that serves customers at their location, like a plumber or cleaner, rather than at a storefront. Google lets these businesses hide their address and list service areas instead.
- Sitemap (XML)
- A file that lists the important URLs on your site to help search engines find them. Submit it in Google Search Console and Bing Webmaster Tools.
- SSL and HTTPS
- Security technology that encrypts the connection between a visitor and your website. Pages should load on https, which is also a light ranking signal.
T3 terms
- Technical SEO
- Work that helps search engines crawl, render and index a site, such as fixing speed, redirects, canonical tags, sitemaps and structured data.
- Title tag
- The HTML title of a page, usually shown as the clickable headline in search results. It should be unique, descriptive and include the main keyword.
- Topical authority
- The depth and quality of a site's coverage of a subject. Sites that cover a topic thoroughly tend to rank more easily for related searches.
U1 term
- URL slug
- The part of a web address after the domain that identifies a page, such as /seo-glossary/. Short, readable slugs work best.
W1 term
- White hat SEO
- SEO that follows search engine guidelines and focuses on helpful content, sound technical work and earned links. It is slower than shortcuts but lasts.
Z1 term
- Zero-click search
- A search where the person gets their answer directly on the results page, from a snippet, map or AI answer, without clicking any website.
Start here
The 10 terms worth knowing first
If you only learn a handful of these, start with the ones that come up in almost every conversation about rankings.
Search intent
Why people search, which decides what kind of page can rank.
Keyword
What people type, and the foundation of every page plan.
Indexing
Whether Google has stored your page at all.
Title tag
Your headline in search results.
Backlink
Another website vouching for yours.
Google Business Profile
Your listing on Google Maps.
Local pack
The three map results most local customers click.
Core Web Vitals
How fast and stable your pages feel.
Schema markup
Code that helps search engines understand your page.
Google AI Overviews
The AI answers now shown above many results.
Reading reports
How to use this glossary with your SEO reports
Monthly SEO reports are full of these terms. When you read yours, focus on a few questions: are impressions and clicks growing, are more of your important pages indexed, are you gaining referring domains from relevant sites, and are you appearing in the local pack for the searches that bring customers?
If a report cannot answer those questions in plain words, ask why. A good SEO partner should be able to explain every number without hiding behind jargon. For a practical list of what to actually do with these ideas, work through our complete SEO checklist.
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Client portal
Every term in your report, backed by real data
Every MarketingFlow client gets a login to our client portal. No guessing, no vague monthly emails. You can see the work and the results whenever you want.
Outreach backlink analytics
Every outreach backlink we build for you each month is listed with clear analytics, and the backlink data is updated every week.
Keyword and page rankings
Your keyword rankings and page rankings come straight from Google. We are approved for Google API data, so the numbers are Google's own.
Indexed pages
See which of your pages Google has indexed, pulled directly from Google, so you know your important pages can actually be found.
Clicks and impressions
Track how many times your site appears in Google search and how many people click through, month by month.
Domain Rating from Ahrefs
Watch your website's Domain Rating (DR), provided by Ahrefs, grow as your backlink profile gets stronger.
Blog content calendar
On the Growth ($290) and Authority ($499) plans, a calendar shows every upcoming article and the exact date it will be posted.
Clear data for every customer, so you can always see what is being done and what it is achieving.
Client portal loginFAQ
SEO glossary questions
What does SEO stand for?
SEO stands for search engine optimization: improving a website so it appears higher in unpaid search results on Google, Bing and AI search tools.
What is a SERP?
SERP stands for search engine results page, the page you see after searching. It can include ads, maps, AI answers and regular results.
What is the difference between on-page and off-page SEO?
On-page SEO is work on your own pages, like titles, content and internal links. Off-page SEO happens elsewhere, mainly earning backlinks and mentions from other websites.
What is a canonical tag?
A canonical tag tells search engines which URL is the main version of a page, so duplicate versions do not split your rankings.
What is a backlink?
A backlink is a link from another website to yours. Links from relevant, trusted sites help search engines see your site as authoritative.
What is E-E-A-T?
E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness, the qualities Google's guidelines use to describe reliable content.
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