Octave

Part of speech: noun

Pronunciation: /ˈɒktɪv/

Definitions

1. A musical interval spanning eight letter-named notes from one pitch to its double or half frequency, or eight consecutive days starting from a religious feast
2. An eight-note sequence in music where the upper pitch vibrates twice as fast as the lower one, or a period of eight days following a liturgical celebration
3. The distance between one musical tone and another with double its frequency, typically covering eight scale degrees ; a religious observance lasting eight days after a feast day

Etymology: The word "octave" comes from Latin "octavus," meaning "eighth," and it is the same root behind "octavo," the book format where a sheet is folded into eight leaves. Musicians counted the interval from the first note of a scale to the eighth, which is why the note sounds like the same letter name returning, now at double the frequency. "Ochava" and "oitava," Spanish and Portuguese forms, are doublets of this word, meaning they descend from the same Latin source by separate routes. The word has a second, older sense that has nothing to do with music. In the Church, an octave was the period of eight days following a major feast, during which the celebration continued, with the last day closing the observance. The day counting was inclusive, so the feast and its octave together spanned a full week plus one day. Music took the term later, applying the same logic of counting the eighth step of a sequence to the eighth note of a scale.

Synonyms: eight, interval, series, scale, note