—octaval /ok tay"veuhl, ok"teuh-/, adj./ok"tiv, -tayv/, n.1. Music.a. a tone on the eighth degree from a given tone.b. the interval encompassed by such tones.c. the harmonic combination of such tones.d. 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.a. a group of eight lines of verse, esp. the first eight lines of a sonnet in the Italian form. Cf. sestet (def. 1).b. a stanza of eight lines.5. the eighth of a series.6. Eccles.a. the eighth day from a feast day, counting the feast day as the first.b. 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.adj.9. pitched an octave higher.[1300-50; ME < L octava eighth part, n. use of fem. of octavus, equiv. to oct- OCT- + -avus adj. suffix]
* * *▪ musicin music, an interval whose higher note has a sound-wave frequency of vibration twice that of its lower note. Thus the international standard pitch A above middle C vibrates at 440 hertz (cycles per second); the octave above this A vibrates at 880 hertz, while the octave below it vibrates at 220 hertz.Because of the close acoustic relationship between two notes an octave apart, the upper A is perceived as qualitatively identical to the lower A, although at a higher pitch. Many musical scales (scale) encompass an octave; in the diatonic scales (major, minor, and modal) of Western music, the octave is an interval of eight notes. It is the only interval to appear as a constant in the musical scales of nearly every culture.In harmony and in instrumentation, a note paired with its octave is said to be doubled. Melodic doubling in octaves is ubiquitous in all types of instrumental music.
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