Abbreviation for ottava bassa or "at the octave below." This indication is found below specific notes on a staff and indicates that those notes should be performed one octave lower than written. This indication can be used with a dotted line that covers a series of notes to be performed at the octave below. The dotted line should end with a upstroke to indicate the end of the passage to be altered. The end of the passage can also be indicated by the term loco ("at place") or perform at the written pitch. This is a relatively new indication and is used in the modern music notation computer programs to replace the traditional 8va bassa, 8a b and simply 8.This indication is used for two reasons. First, it provides a shorthand for composers and copyists to keep from writing music with numerous ledger lines. Second, it is often preferable to performers who have a more difficult time reading ledger lines than notes on the staff.Also 8va bassa, 8a b, 8.