What is a meta tag?
An HTML element in the `<head>` that supplies metadata about the page, title, description, viewport, social previews, robots directives.
<meta> tags don't render anything visible. They communicate metadata to browsers, search engines, and social platforms. The most important ones in 2026 are: <title> (technically not a meta tag, but plays the same role), <meta name="description"> for SERP snippets, <meta name="viewport"> for mobile, and the Open Graph and Twitter Card tags for social previews.
For SEO specifically, the description meta tag is no longer a ranking signal but is still what Google often shows under your SERP entry. Writing it well (150-160 characters, action-oriented, with a clear value proposition) directly affects click-through rate even when it has no impact on rank.
Other useful meta tags: <meta name="robots" content="noindex"> to keep a page out of search, <meta name="theme-color"> for mobile browser chrome, <meta charset="utf-8"> for character encoding (always first in <head>).