Clef
musical symbol used to indicate the pitch of written notes / From Wikipedia, the free encyclopedia
A clef is a sign at the beginning of a staff of music which makes it possible for the player to work out what the notes are. The word “clef” is a French word meaning “key”. The original Latin word is “clavis”. It is the “key” to understanding which notes should be played.
The staff (or “stave”) consists of five lines across the page. The notes are placed on these lines and in these spaces. The staff is only large enough to cover one and a half octaves of music (a bit more with ledger lines). Therefore, different clefs are used for high music and for low music.