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Definition: An octave is a musical interval with the distance of:

  • 12 half steps in the chromatic scale.
  • 7 or 8 notes in the diatonic scale.
    (An octave consists of 7 unique notes, but spans 8; octo is Latin for “eight.”)

Two notes spaced one octave apart sound similar, despite one being higher in pitch. This is because the higher note’s frequency (its pattern of sound waves) is double the speed of the lower note, but that pattern is the same for both notes - this is the similarity your ear is observing.

For example, middle C (C4) is half the frequency of C5, but they both share the same pattern of sound waves; those waves simply repeat twice as fast in the pitch of C5.

Octave can be abbreviated P8, meaning “perfect eighth” or “perfect octave”; or 8va, meaning “ottava.”

  • View the piano keys labeled with their frequencies

Also Known As:

  • ottava (It)
  • octave (En + Fr)
  • Oktave (Ger)
  • octava (Sp + Lat.)

Pronunciation: ok'-tiv

More Musical Terms: