String

From VideoLAN Wiki

A string is a piece of text: a string of characters.

If the string has spaces, and you're using entering text on a terminal, then you should put it in quotation marks. You can put quotes arround any other string on a terminal, too.

For example, in

% vlc "my file.avi"

the text my file.avi is a string saying where the file to be opened is.