pentad Meaning, Definition & Usage

  1. noun the cardinal number that is the sum of four and one
    quintet; quintuplet; quint; Little Phoebe; cinque; fivesome; 5; Phoebe; V; five; fin.

WordNet

Pen"tad noun
Etymology
Gr. , , a body of five, fr. five.
Definitions
  1. (Chem.) 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.
Pen"tad adjective
Definitions
  1. (Chem.) Having the valence of a pentad.

Webster 1913