octave

American  

[ok-tiv, -teyv] / ˈɒk tɪv, -teɪv /

noun

1. Music.

   1. a tone on the eighth degree from a given tone.

   2. the interval encompassed by such tones.

   3. the harmonic combination of such tones.

   4. a series of tones, or of keys of an instrument, extending through this interval.

2. a pipe-organ stop whose pipes give tones an octave above the normal pitch of the keys used.

3. a series or group of eight.

4. Also called octet.  Prosody.

   1. a group of eight lines of verse, especially the first eight lines of a sonnet in the Italian form.

   2. a stanza of eight lines.

5. the eighth of a series.

6. Ecclesiastical.

   1. the eighth day from a feast day, counting the feast day as the first.

   2. the period of eight days beginning with a feast day.

7. one eighth of a pipe of wine.

8. Fencing. the eighth of eight defensive positions.

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adjective

1. pitched an octave higher.

octave British  

/ ˈɒktɪv /

noun

1. 1. the interval between two musical notes one of which has twice the pitch of the other and lies eight notes away from it counting inclusively along the diatonic scale

   2. one of these two notes, esp the one of higher pitch

   3. ( as modifier ) See also perfect diminished interval

      an octave leap

2. prosody a rhythmic group of eight lines of verse

3. 1. a feast day and the seven days following

   2. the final day of this period

4. the eighth of eight basic positions in fencing

5. any set or series of eight

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adjective

1. consisting of eight parts

octave Cultural  

1. An interval between musical notes in which the higher note is six whole tones, or twelve half tones, above the lower. From the standpoint of physics, the higher note has twice the frequency of the lower. Notes that are an octave apart, or a whole number of octaves apart, sound in some ways like the same note and have the same letter for their names.

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Other Word Forms

• octaval adjective

Etymology

Origin of octave

1300–50; Middle English < Latin octāva eighth part, noun use of feminine of octāvus, equivalent to oct- oct- + -āvus adj. suffix

Explanation

An octave is a musical interval of eight notes. Sing from “do” to “do” — on key — and you will have an octave. Like octagon and octopus, the key to an octave is “eight.” An octave may be the entire eight-note scale, or just the bottom and top notes, like C and C. Octave can also refer to an eight-line group in an Italian sonnet, or an eight-day festival; in fact, the word comes from the Latin expression octava dies, meaning “eighth day” — as in the eighth festival day after a feast. The ave in octave is usually pronounced “iv.”

Example Sentences

Ferran, whose theatrical octave range is nothing short of astonishing, earns the sentiment in a way that I wasn’t sure was possible at this stage of the play’s existence.

From Los Angeles Times • Mar. 11, 2025

It became a defining song for the genre, marrying Thomas's gospel-trained, four octave vocals to a pulsing electronic beat.

From BBC • Jul. 22, 2024

So if there’s 13 notes to the octave, a minor ninth or 13 semitones sounds like an octave when you play it on the keyboard.

From New York Times • Feb. 11, 2024

In the musical analogy, important musical intervals based on ratios of frequencies are the fourth, 4:3, the fifth, 3:2, and the octave, 2:1.

From Salon • Feb. 6, 2024

The twelve-note octave as we know it became a firm fixture of Western music after the publication in 1722 of J. S. Bach’s forty-eight preludes and fugues for the 'Well-Tempered Keyboard’.

From "The Story of Music" by Howard Goodall