A snippet is a short excerpt from a page.

Snippets are for instance the excerpts displayed in search results by search engines. Their purpose is to summarize the information from the page, draw the users' attention on them and encourage them to click on the link to the page.

This snippet can be defined in the HTML source code of the page and should be between 200 and 300 characters long. If there is no description element available to generate the snippet from it, the snippet will be generated from the text on the page.