1. A stanza or verse form of eight lines, typically in iambic pentameter, used especially in Italian poetry.
Usage: literary; also called ottava rima when referring to the rhyme scheme
2. In music, an interval spanning eight diatonic scale degrees, or the eighth note above or below a given note.
Usage: musical term; often abbreviated as 8va in musical notation

Examples

• The poet composed an ottava in the style of Dante.
• Ottava rima became popular in Renaissance Italian literature.
• The soprano sang the melody an ottava higher than written.
• In the score, the instruction '8va' indicates the notes should be played an ottava above the staff.
• The ottava is one of the most fundamental intervals in Western music theory.