Glossary

On-page SEO

Titles, headings, internal links and the on-page signals that tell a search engine what a page is about.

38 terms, each answer-first and checked against a primary source.

above the fold Above the fold is the part of a web page visible in the browser viewport before any scrolling. In SEO it matters because that space shapes the first impression, usually holds the Largest Contentful Paint element, and is where Google expects to find real content rather than stacked ads.
alt text Alt text (the HTML alt attribute) is a written description of an image that screen readers announce, that browsers show when the image fails to load, and that search engines read to understand what the picture depicts. Google also uses it as anchor text when the image is a link.
anchor link An anchor link is a hyperlink that jumps to a specific section of a page using a URL fragment (the part after the # symbol) that matches an element's id attribute. Clicking it scrolls the browser straight to that section instead of loading a new page.
canonical URL A canonical URL is the single web address you designate as the master copy of a set of duplicate or near-identical pages. Google consolidates ranking signals onto it and usually shows that version in search results, though it treats your choice as a hint, not a rule.
content structure Content structure is how a page organizes its information: the heading hierarchy (H1 through H6), sections, paragraphs, and lists that give the page a logical outline. Clear structure helps readers skim, helps search engines identify topics, and helps AI answer engines pull clean, citable passages.
focus keyword A focus keyword (also called a focus keyphrase) is the single main search query a page is written and optimized to rank for. It guides the page's title, headings, and body copy, so one page targets one primary term.
H1 tag An H1 tag is the top-level HTML heading (<h1>) that names a web page's main topic. Search engines and screen readers read it as the page's primary subject, and Google can use it to build the clickable title link shown in search results.
H2 tag An H2 tag is an HTML second-level heading (<h2>) that labels a major section of a page beneath the single H1. It breaks content into scannable subtopics for readers, screen readers, and search engines that parse a page's heading outline.
H3 tag An H3 tag (<h3>) is a third-level HTML heading that labels a subsection nested inside an H2 section. It splits a larger topic into smaller, scannable parts, giving readers and search engines finer structure within the page.
header tags Header tags (also called heading tags) are the HTML elements <h1> through <h6> that label sections of a page and define its content hierarchy, with <h1> the top level and <h6> the lowest. They help readers skim and let browsers and assistive tech build a structural outline of the page.
heading hierarchy Heading hierarchy is the logical nesting of a page's HTML heading elements (H1 through H6) so their levels descend in order without skipping a rank. It gives the page an outline: one H1 as the title, H2s for main sections, and H3s for subsections beneath them.
image file name An image file name is the descriptive text you give an image before its extension, like black-labrador-puppy.jpg. Google reads it as a light signal for understanding and ranking pictures in Google Images, so short, descriptive, hyphen-separated names beat generic ones like IMG_0042.jpg.
image optimization Image optimization is the practice of compressing, sizing, naming, and tagging images so they load fast and can appear in image search. It spans file format (WebP or AVIF), file weight, descriptive filenames and alt text, responsive srcset markup, and lazy-loading images below the fold.
image title attribute The image title attribute is an optional title value on an HTML img tag that most browsers show as a tooltip when a visitor hovers over the image. It carries little to no SEO weight; Google's image guidelines never mention it and it isn't used for ranking.
internal linking Internal linking is the practice of adding hyperlinks from one page of a website to another page on the same site. These links help search engines discover pages, pass ranking signals like PageRank between them, and help users navigate.
keyword placement Keyword placement is positioning a page's target terms in the spots search engines weight most: the title element, H1, opening paragraph, subheadings, URL, image alt text, and internal anchor text. Google reads these as topic signals but rewards natural phrasing over repeated exact matches.
keyword prominence Keyword prominence is an on-page factor describing how early and how visibly your target term appears in a page's most weighted spots: the title tag, the H1, the opening paragraph, and the URL. The earlier and more prominent the placement, the faster search engines grasp what the page is about.
meta description A meta description is a short HTML tag in a page's head that summarizes the page's content. Google may show it as the snippet beneath the title in search results, so it shapes click-through, but it is not a direct ranking factor.
meta description length Meta description length is how long a page's meta description tag is, measured in characters or pixels. Google sets no fixed limit and truncates the snippet to fit the device width, but common practice targets about 155 to 160 characters on desktop and roughly 120 on mobile so the summary shows in full.
meta keywords The meta keywords tag is a legacy HTML meta element in a page's head that listed the keywords a page wanted to rank for. Google has ignored it for web ranking since 2009, and no major search engine treats it as a positive ranking signal today.
meta tags Meta tags are HTML <meta> elements in a page's <head> that describe the page to browsers and search engines. Google supports a specific set (including description, robots, and viewport) and ignores others, such as the keywords meta tag.
next-gen image formats Next-gen image formats are modern image file types, mainly WebP and AVIF, that compress photos and graphics far smaller than JPEG or PNG at the same visual quality. Google's Lighthouse flags pages still serving older formats under its "Serve images in modern formats" audit.
NLP SEO NLP SEO is optimizing content so search engines' natural-language processing models (such as Google's BERT and MUM) can correctly parse its meaning, entities, and intent. It favors clear, entity-rich, conversational writing over isolated keyword matching.
on-page SEO On-page SEO is the practice of optimizing elements on the page itself (the content, HTML tags like the title and headings, images, and internal links) so search engines and readers can clearly tell what the page is about and rank it for the right queries.
Open Graph tags Open Graph tags are meta tags in a page's head that tell social and messaging platforms how to render a link when it is shared, setting the preview title, description, and image. They follow the Open Graph protocol format: <meta property="og:title" content="..." />.
outbound links Outbound links (also called external links) are hyperlinks on your page that point to a page on a different domain. They cite the sources your content relies on and signal to readers and search engines which sites you trust. Google treats them as normal citations, not a direct ranking boost.
permalink A permalink (permanent link) is the full, stable URL assigned to a single web page or post. It is meant to stay the same for the life of that content so readers, other sites, and search engines can always reach the page at the same address.
readability Readability is how easy a page's text is to read and understand, often scored by formulas like Flesch Reading Ease or Flesch-Kincaid grade level. Google does not treat readability as a direct ranking factor, but hard-to-read copy weakens engagement and clarity, which do matter for SEO.
responsive images Responsive images serve an appropriately sized version of an image to each device using the HTML srcset and sizes attributes (or the picture element), so a phone downloads a small file and a large retina desktop gets a sharp one. This cuts wasted bytes and speeds page load.
secondary keywords Secondary keywords are related search terms a page targets alongside its primary keyword. They share the primary term's intent but use different phrasing (synonyms, variations, subtopics), so one page can rank for many queries instead of just one.
semantic HTML Semantic HTML is the practice of choosing HTML tags for their meaning rather than their appearance, so elements like article, nav, header, and h1 tell browsers, assistive tech, and search crawlers what content is. Plain div and span carry no such meaning.
SEO-friendly URL An SEO-friendly URL is a short, readable web address that uses real words and hyphens to describe the page, so both people and search engines can tell what it is about from the URL alone. Example: /services/on-page-seo/ instead of /page?id=42&cat=3a5.
table of contents A table of contents (TOC) in SEO is an on-page list of anchor links that jump to sections of the same page, built with URL fragments (#section) tied to id attributes on your headings. It helps readers navigate long content and can prompt Google to show "jump to" links under your search result.
title tag A title tag is the HTML <title> element that sets a page's title. Google uses it as the clickable headline (the "title link") in search results, and browsers show it in the tab. It is a confirmed but minor ranking signal and the main text that wins or loses the click.
title tag length There is no hard character limit on a title tag, but Google truncates the title link to fit the device width, roughly 600 pixels (about 50 to 60 characters) on desktop. Keeping titles near that range prevents cut-off and reduces the chance Google rewrites them.
Twitter Cards Twitter Cards (now called X Cards) are HTML meta tags that control how a link previews when it is shared on X. Adding a twitter:card tag plus title, description, and image tags turns a bare URL into a rich card with a headline, summary, and thumbnail.
URL slug A URL slug is the human-readable part of a web address that identifies a specific page, usually the segment after the domain and any subfolders (for example, "url-slug" in seobro.com/glossary/url-slug). It is normally generated from the page title and can be edited.
word count Word count is the total number of words on a page. Google says it is not a ranking factor or quality signal, so there is no ideal length that lifts rankings. Content should be as long as the query needs, and no longer.