octad [
'ɑktæd]
n. 八个一组, 八阶物
[化] 八价物; 八价的; 八素组
[医] 八价元素
octad[ noun ]
the cardinal number that is the sum of seven and one
<noun.quantity>
Octad \Oc"tad\, n. [Gr. ?, ?, the number eight.]
1. (Chem.) An atom or radical which has a valence of eight,
or is octavalent.
2. A group of eight things.
[PJC]