Sometimes called a "charsheet" if you can't be bothered with those two extra syllables. It's a sheet (probably of paper) that has information about your character on it. You make it during character generation. At a minimum, it contains all of your character's stats and an equipment list. Certain crunchier games have character sheets that are expected to run across multiple pages. Some people like to put a bunch of extra information on the sheet, like a background story, and maybe an entire campaign journal. In the case of Warhammer Fantasy, you can actually buy a "character folio" that gives headings and space for all sorts of non-vital information.