1. [syn: seven, 7, VII, sevener, heptad, septet, septenary]
The Collaborative International Dictionary of English v.0.48:
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.
WordNet (r) 3.0 (2006):
n 1: the cardinal number that is the sum of six and one [syn:
seven, 7, VII, sevener, heptad, septet,