- a tone on the eighth degree from a given tone.
- the interval encompassed by such tones.
- the harmonic combination of such tones.
- a series of tones, or of keys of an instrument, extending through this interval.
- a pipe-organ stop whose pipes give tones an octave above the normal pitch of the keys used.
- a series or group of eight.
- Also called octet. Prosody.
- a group of eight lines of verse, especially the first eight lines of a sonnet in the Italian form.Compare sestet(def 1).
- a stanza of eight lines.
- the eighth of a series.
- the eighth day from a feast day, counting the feast day as the first.
- the period of eight days beginning with a feast day.
- one eighth of a pipe of wine.
- Fencing. the eighth of eight defensive positions.
- pitched an octave higher.
- 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
- one of these two notes, esp the one of higher pitch
- (as modifier)an octave leap See also perfect (def. 9), diminished (def. 2), interval (def. 5)
- prosody a rhythmic group of eight lines of verse
- a feast day and the seven days following
- the final day of this period
- the eighth of eight basic positions in fencing
- any set or series of eight
- consisting of eight parts
n.c.1300, utaves (plural, via Anglo-French from popular Old French form oitieve, otaves), reformed in early 15c., from Medieval Latin octava, from Latin octava dies “eighth day,” fem. of octavus “eighth,” from octo (see eight). Originally “period of eight days after a festival,” also “eighth day after a festival” (counting both days, by inclusive reckoning, thus if the festival was on a Sunday, the octaves would be the following Sunday). Verse sense of “stanza of eight lines” is from 1580s; musical sense of “note eight diatonic degrees above (or below) a given note” is first recorded 1650s, from Latin octava (pars) “eighth part.” Formerly English eighth was used in this sense (mid-15c.) 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.