Hexad
Pronunciation : Hex"ad
Part of Speech : n.
Etymology : [L. hexas, hexadis, the number six, Gr. (chem.)
Definition : Defn: An atom whose valence is six, and which can be theoretically combined with, substituted for, or replaced by, six monad atoms or radicals; as, sulphur is a hexad in sulphuric acid. Also used as an adjective.
Source : Webster's Unabridged Dictionary, 1913