What is a meta description?

A meta description is the short snippet of text — about 150 to 160 characters — that Google often shows under your page title in search results:

• Not a ranking factor — Google confirmed years ago that what you write there does not move your position.
• It affects clicks — the description is your one line of ad copy in the results, and Google will rewrite it from your page content if yours is missing, too long, or does not match the query.
• The practical move — a description that answers the searcher’s question and names what you do and where — “Licensed electrician in Geelong, same-day callouts” beats a generic company tagline.
• One per page — each page should have its own; the common mistake is the same description repeated site-wide.

The meta description does not change your ranking; it changes how many people click the ranking you already have.