[ahl uh-tah-vuh; Italian ahl-lawt-tah-vah]
a direction (8va), placed above or below the staff to indicate that the passage covered is to be played one octave higher or lower respectively.
Origin of all' ottava
1815–25; < Italian: literally, at the octave
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019