Found 2 items, similar to Heptad.
English → English (WordNet) Definition: heptad heptad n : the cardinal number that is the sum of six and one [syn: seven, 7, VII, sevener, septet]
English → English (gcide) Definition: Heptad 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]