Category:Dyad

Dy"ad, n. Etym: [L. dyas, dyadis, the number two. Gr. dyade. See two, and cf. Duad.]

1. Two units treated as one; a couple; a pair.

2. (Chem.)

Defn: An element, atom, or radical having a valence or combining power of two.

dyad Dy"ad, a. (Chem.)

Defn: Having a valence or combining power of two; capable of being substituted for, combined with, or replaced by, two atoms of hydrogen; as, oxygen and calcium are dyad elements. See Valence.