octad

Noun

WordNet 3.0

the cardinal number that is the sum of seven and oneSynonyms: eight 8 VIII eighter eighter from Decatur ogdoad octonary octet

Octad \Oc"tad\, n. [Gr. ?, ?, the number eight.]

1.(Chem.) An atom or radical which has a valence of eight, or is octavalent. [1913 Webster]

2.A group of eight things. [PJC]