1. pentad - Noun
2. pentad - Adjective
Any element, atom, or radical, having a valence of five, or which can be combined with, substituted for, or compared with, five atoms of hydrogen or other monad; as, nitrogen is a pentad in the ammonium compounds.
Having the valence of a pentad.
Source: Webster's dictionaryEach quintuple (pentad) occurs once. Source: Internet
Among his influential concepts are "identification," "consubstantiality," and the "dramatistic pentad." Source: Internet