Main Entry: oc·tave

Pronunciation: \ˈäk-tiv, -təv, -ˌtāv\

Function: noun

Etymology: Middle English, from Anglo-French, from Medieval Latin octava, from Latin, feminine of octavus eighth, from octo eight — more at eight

Date: 14th century

1 : an 8-day period of observances beginning with a festival day
2 a : a stanza of eight lines : ottava rima b : the first eight lines of an Italian sonnet
3 a : a musical interval embracing eight diatonic degrees b : a tone or note at this interval c : the harmonic combination of two tones an octave apart d : the whole series of notes, tones, or digitals comprised within this interval and forming the unit of the modern scale e : an organ stop giving tones an octave above those corresponding to the keys
4 : the interval between two frequencies (as in an electromagnetic spectrum) having a ratio of 2 to 1
5 : a group of eight