heptad : Dictionary / Wörterbuch (BEOLINGUS, TU Chemnitz)

English Dictionary: heptad	by the DICT Development Group
2 results for heptad
From WordNet (r) 3.0 (2006) [wn]:
heptad n the cardinal number that is the sum of six and one [syn: seven, 7, VII, sevener, heptad, septet, septenary]
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
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.