[1] : The Collaborative International Dictionary of English v.0.48

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

[2] : WordNet (r) 2.0

octad
     n : the cardinal number that is the sum of seven and one syn: eight,
          8, viii, eighter, eighter from decatur, ogdoad,
          octonary, octet
see also:
eight 8 viii eighter eighter from decatur ogdoad 
octonary octet 

Octad >> O Words
Octad, definition of term: Octad
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