Terms - Number
12-bar blues
12-bar minor blues
15ma
15mb
16-bar blues
1°
2 ped
2°
3°
4°
8
15
8-bar blues
8°
8a alta
8a b.
8va
8va bassa
8vb
8vo

8

[Abbreviation, 8va or 8vb]

1. This is an abbreviation for at the octave. It is an indication to perform a specific note or passage one octave higher or lower than written. If the 8 appears above a note or passage, it is the abbreviation for 8va and the note or passage should be performed one octave higher than written. If the 8 appears below a note or passage, it is the abbreviation for 8vb and the note or passage should be performed one octave lower than written.

See also [Eng.] at the octave; [Fr.] à l'octave; [Ger.] in der Oktave; [It.] all' ottava; [It.] ottava; [It.] ottava bass; [Abbr.] 8va; [Abbr.] 8a alta; [Abbr.] 8vb; [Abbr.] 8va bassa; [Abbr.] 8a b.

2. The number that appears above or below the treble clef or bass clef symbol to indicate that the indicated passage or staff of the composition should be performed at the octave. The number above the clef symbol indicates the music should be performed one octave higher than notated and the number below the clef symbol indicates that the music should be performed one octave lower than notated. These clefs are often called octave clefs.

Octave Clefs
Name and Indication	Symbol	Name and Indication	Symbol
Octave treble clef Perform One Octave Higher		Octave treble clef (Vocal tenor clef) Perform One Octave Lower
Octave bass clef Perform One Octave Higher		Octave bass clef Perform One Octave Lower

See more about octave clefs.

Octave Clefs