What is a snippet?
A snippet is a brief “summary of document content” displayed in search results directly under the title of the found page.
A snippet enables user to get some idea of a document, or even the required information, without following the link.
How can I change the title and the description of a site in search results?
The description is generated automatically using quotations from the text of the discovered document, and the title is based on "title" document tag. By changing document texts and titles on your site, you will change the description of the site in search results.