tablature
A notation system showing finger positions rather than musical pitches, commonly used for guitar.
In Depth
Tablature (or tab) uses lines representing strings and numbers indicating fret positions, telling the player exactly where to place their fingers. Guitar tablature has six lines (one per string), with numbers showing which fret to press. A 0 means play the open string, a 3 means press the third fret.
Tablature predates modern notation — lute tablature was one of the first systems for writing down instrumental music in the Renaissance. Today, guitar tabs are the most widely distributed form of musical notation on the internet, making music accessible to millions who cannot read standard notation. Tablature has limitations, however — it specifies position but not rhythm, and it is instrument-specific.
Guitar tablature is so widespread online that more music is probably distributed as tabs than as standard notation — making it arguably the most-read notation system in the world today.