1. The eighth day after a church festival, the festival day being included; also, the week following a church festival. "The octaves of Easter." Jer. Taylor.
2. (Mus.) (a) The eighth tone in the scale; the interval between one and eight of the scale, or any interval of equal length; an interval of five tones and two semitones. (b) The whole diatonic scale itself.
Note: The ratio of a musical tone to its octave above is 1:2 as regards the number of vibrations producing the tones.
3. (Poet.)
Defn: The first two stanzas of a sonnet, consisting of four verses each; a stanza of eight lines. With mournful melody it continued this octave. Sir P. Sidney. Double octave. (Mus.) See under Double. — Octave flute (Mus.), a small flute, the tones of which range an octave higher than those of the German or ordinary flute; — called also piccolo. See Piccolo.
4. A small cask of wine, the eighth part of a pipe.
OCTAVE
Oc"tave, a.
Defn: Consisting of eight; eight. Dryden.
OCTAVO Oc*ta"vo, n.;pl. Octavos. Etym: [L. in octavo; in in + octavo, abl. of octavus. See Octave.]
Defn: A book composed of sheets each of which is folded into eight leaves; hence, indicating more or less definitely a size of book so made; — usually written 8vo or 8º.