Glossary /On-page & content
Meta Description
A short summary of a page that engines may use as its results-page snippet. Not a ranking factor, but it decides clicks.
The meta description is a proposed snippet. It has not been a ranking factor for many years, and engines replace it whenever a passage from the page fits the query better — which is most of the time for long-tail queries. Roughly two thirds of snippets end up rewritten.
That does not make it worthless. When it is used, it is the sales copy under the headline, and the difference between a description that states what the reader will get and one that recites the company boilerplate shows up directly in click-through rate.
The practical approach is to write it as a promise about the page’s content, keep it near 150 characters so it survives truncation, and make it unique per page. Auto-generating them from the first paragraph is better than leaving them empty and better than duplicating one across a template.