You open an SEO article, or a tool dashboard, or an email from an agency, and it reads like a foreign language. SERP, CTR, backlink, canonical tag, domain authority. Everyone around you seems to nod along, and you’re left guessing what half of it means from context.
This glossary is the translator. Read through it once, and you’ll be able to open Google Search Console, skim an SEO blog post, or sit through a call with an agency without stopping every third sentence to look something up. If you want the fuller picture of what SEO actually is and why it matters, start with What Is Search Engine Optimization?. This post is the reference you come back to when a specific word trips you up.
Each term below gets a plain definition and a real example of how you’d actually run into it, in a dashboard, in an article, or in a conversation with an agency. Bookmark this page. You won’t need all of it today, but you’ll need pieces of it constantly.
Search basics
SEO (search engine optimization). The practice of adjusting your website so search engines understand it and show it to people searching for related things. Example: an agency tells you “we’re doing SEO work on your site,” meaning they’re changing pages, links, and content to help you show up in Google.
Search engine. A website that takes a person’s typed question and returns a list of relevant pages, like Google, Bing, or DuckDuckGo. Example: when someone types “plumber near me” into Google, Google is the search engine doing the matching.
SERP (search engine results page). The page of results you see after running a search. Example: a tool might say “you rank #4 on the SERP for ‘plumber near me,’” meaning your page is the fourth listing down.
Organic results. The regular search listings shown because a search engine’s algorithm ranked them there, not because anyone paid for the placement. Example: SEO work aims to improve your position in organic results, separate from any ads on the page.
Paid results. Listings marked “Ad” or “Sponsored” that a business paid to have shown for a specific search. Example: those top few listings with a small “Ad” label are paid results, and SEO has no direct effect on them.
Keyword. A word or phrase a person types into a search engine. Example: a tool dashboard might list “emergency plumber Chicago” as a keyword you’re targeting.
Search intent. What the person actually wants when they type a search, beyond the literal words. Example: someone searching “plumber pricing” probably wants to compare costs, while “plumber near me” means they want to hire someone right now.
What search engines do
Crawling. The process where a search engine sends automated programs to visit pages on your site and read their content. Example: in Search Console you might see “last crawled 2 days ago” next to one of your pages.
Indexing. After crawling a page, the search engine stores it in a giant database so it can be shown in results later. Example: a page can be crawled but not indexed, which means Google looked at it but decided not to add it to its list of searchable pages.
Ranking. The process of deciding, for a given search, which indexed pages to show and in what order. Example: your indexed page might rank #15 for one keyword and not appear at all for another.
Crawler / bot. The automated program a search engine uses to visit and read pages, sometimes called a spider. Example: Google’s crawler is named Googlebot, and you’ll see that name in your site’s server logs.
Sitemap. A file on your site that lists your pages so search engines can find them more easily. Example: you might submit a file at yoursite.com/sitemap.xml through Search Console.
Robots.txt. A small text file that tells crawlers which parts of your site they’re allowed or not allowed to visit. Example: an agency might say “we blocked the staging folder in robots.txt” to keep it out of search results.
On-page terms
Title tag. The clickable headline text that shows up in search results for a page, set in the page’s HTML. Example: in a tool like Yoast, you’ll see a box labeled “SEO Title” where you write this.
Meta description. The short paragraph of text under the title tag in search results, meant to summarize the page and encourage a click. Example: you write one or two sentences here, and Google sometimes uses them, sometimes rewrites them based on the search.
Heading (H1, H2). The labeled headline levels in a page’s content, with H1 usually the main title and H2s marking major sections. Example: this glossary uses H2 headings like “Search basics” to break up each cluster of terms.
Alt text. A short written description attached to an image, read by screen readers and search engines since neither can “see” a picture. Example: an image of a golden retriever might have alt text reading “golden retriever running on a beach.”
Internal link. A link from one page on your site to another page on the same site. Example: this post links internally to the SEO tools guide because it’s relevant to a term further down.
Canonical tag. A tag in a page’s code that tells search engines “treat this other URL as the main version” when similar or duplicate pages exist. Example: a product available at three different URLs might all point their canonical tag to one preferred URL.
Authority and links
Backlink. A link from another website pointing to yours. Example: if a local news site links to your business page, that’s a backlink, and it can be one reason you rank higher.
Anchor text. The clickable words in a link. Example: in the sentence “check out this plumbing guide,” the phrase “plumbing guide” is the anchor text.
Domain authority (DA). A score, created by a specific SEO tool company and not by Google, that estimates how likely a website is to rank well based on its backlinks and other factors. Example: a tool might show your site’s DA as 22, but that number never appears inside Google itself, since Google doesn’t publish or use it. If you want to understand why some competitors seem to out-rank you despite thinner content, Why Does Your Competitor Outrank You on Google? walks through the backlink and authority factors involved.
NAP (name, address, phone). Your business’s core contact details, and how consistently they appear across your website, directories, and listings. Example: if your Google Business Profile lists “123 Main St” but your website footer says “123 Main Street,” that mismatch is a NAP inconsistency.
Metrics you’ll see in tools
Impressions. The number of times your page showed up in search results for any search, whether or not anyone clicked. Example: Search Console might show 500 impressions for a keyword but only 10 clicks.
Click-through rate (CTR). The percentage of people who clicked your listing out of everyone who saw it. Example: 10 clicks out of 500 impressions works out to a 2% CTR. For more on reading these numbers inside the tools that report them, see SEO Tools for Finding Better Opportunities.
Bounce rate. The percentage of visitors who leave your site after viewing only one page, without clicking to another page or taking an action. Example: an analytics dashboard might show a 70% bounce rate for a blog post, a number that by itself doesn’t tell you if that’s good or bad.
Core Web Vitals. A set of Google metrics measuring how fast a page loads and how stable and responsive it feels while loading. Example: a report might flag your homepage for “poor Largest Contentful Paint,” one of the three Core Web Vitals.
Long-tail keyword. A longer, more specific search phrase, usually with lower search volume but clearer intent than a broad term. Example: “SEO” is a broad keyword, while “how to fix crawl errors on a Shopify store” is a long-tail keyword.
Common mistakes or misconceptions
Domain authority is a third-party estimate built by one tool company, not a Google ranking factor. Google has stated directly that it doesn’t use it. Treat it as a rough comparison number between sites, not a score Google checks when ranking pages.
“Indexed” doesn’t mean “ranking well.” A page can sit in Google’s index and still show up on page 8 for every search, or for nothing at all. Indexing is the entry ticket, ranking is a separate contest that happens afterward.
Keyword and search intent are two different ideas. Two searches can use different words and want the same answer, or use the same word and want different things. Content built around the literal keyword while ignoring what the searcher actually wants tends to underperform.
A high bounce rate isn’t automatically bad. Someone who searches “what time zone is Chicago in,” gets the answer instantly, and leaves counts as a bounce, and that’s a perfectly successful visit for that page. Bounce rate becomes a real warning sign only on pages where you wanted the visitor to do something else, like read a related article or fill out a form.
Your next step
Open Google Search Console or Google Analytics for your own site right now. Find three terms from this glossary on the screen: an impressions number, a CTR percentage, and either a Core Web Vitals score or a list of indexed pages. Once you can point at each one and say what it means, the dashboard has already gone from noise to information.
FAQ
What’s the difference between domain authority and PageRank? PageRank was an internal Google metric, largely retired from public view, based on link quality across the web. Domain authority is a separate, unofficial score built by a third-party tool company to estimate a similar idea. Only PageRank was ever actually part of Google’s own system.
Do I need to know all of these terms to do SEO myself? No. Most site owners regularly need only a handful, especially title tags, meta descriptions, keywords, and the metrics inside Search Console. The rest are useful for understanding an agency’s report or a tool’s dashboard when they come up.
Why does Google sometimes rewrite my meta description? Google generates the description shown in search results based on what it judges most relevant to the specific search someone ran, and your written meta description is only one input. This happens most often when your description doesn’t closely match the terms being searched.
Is a backlink always good for my site? Not always. A backlink from a relevant, trustworthy site tends to help, but links from spammy or unrelated sites can be neutral, and a large pattern of them can even get flagged as manipulative.