OCTAD
eight, VIII, eighter, eighter from Decatur, octad, ogdoad, octonary, octet
(noun) the cardinal number that is the sum of seven and one
Source: WordNet® 3.1
Etymology
Noun
octad (plural octads)
A group of eight things.
Synonym: octonary
(historical) hundred million = myriad myriad; 100,000,000 = 108 [from 16th c.]
Coordinate terms
• monad · duad, dyad · triad · tetrad · pentad · hexad · heptad · octad · ennead, nonad · decad, decade · hendecad · dodecad, duodecade
Source: Wiktionary
Oc"tad, n. Etym: [Gr. (Chem.)
Definition: An atom or radical which has a valence of eight, or is
octavalent.
Source: Webster’s Unabridged Dictionary 1913 Edition