Heptad

2 definitions found

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

  Heptad \Hep"tad\, n. [L. heptas the number seven. Gr. ?, ?, fr.
     "epta` seven.] (Chem.)
     An atom which has a valence of seven, and which can be
     theoretically combined with, substituted for, or replaced by,
     seven monad atoms or radicals; as, iodine is a heptad in
     iodic acid. Also used as an adjective.


     [1913 Webster]

From WordNet (r) 2.0 [wn]:

  heptad
       n : the cardinal number that is the sum of six and one [syn: {seven},
            {7}, {VII}, {sevener}, {septet}]