octa-=eight,eighth 变化型 octo-
1 (music 音)
(a) note that is six whole tones above or below a given note 第八音.
(b) space between two such notes 八度
*These notes are an octave apart. 这些音相距八度.
(c) note and its octave played together 八度和音
*The child's hands are too small to stretch to an octave on the piano. 这孩子的手太小, 按不到钢琴上八度和音的键.
(d) note and its octave with the six notes in between 八度音程（包括两个八度音之间的六个音）. Cf 参看 scale2 6.
2 (also octet) (in poetry) first eight lines of a sonnet; verse of eight lines （诗）十四行诗的前八行, 八行诗.
1300-1400; Language: Medieval Latin;Origin:
octava, from Latin
; because there are eight notes in the range]a)
the range of musical notes between the first note of a scale
and the last oneb)
the first and last notes of a musical scale