ottava

 

2. When written above a passage in a composition, this term indicates that the passage should be performed one octave higher than written. When written below a passage in a composition, this term indicates that the passage should be performed one octave lower than written.

 

In modern notation, the abbreviation 8va is used to indicate the passage to be performed one octave higher than written and the abbreviation 8vb (ottava bassa) is used to indicate the passage to be performed one octave lower than written.