Meaning of TRIAD in English

TRIAD

I. ˈtrīˌad, -īəd noun

( -s )

Etymology: Latin triad-, trias, from Greek; akin to Greek treis three — more at three

: a union or group of three especially of three closely related persons, beings, or things : trinity

a triad of deities

a triad of symptoms

as

a. : a gnomic literature in medieval Wales and Ireland consisting of short aphorisms grouped in threes and in prose marked by rhythm and assonance and applying to various subjects (as history, laws, or morals)

b. : a trivalent element, atom, or radical

c. : a chord of three tones consisting of a root with its third and fifth and constituting the harmonic basis of tonal music — called also common chord ; see major triad , minor triad ; compare first inversion , second inversion

d. : a group of three individuals maintaining a sociologically significant relationship — compare dyad

e. : a group of three strophes in a classical ode consisting of strophe, antistrophe, and epode

II. adjective

: having symmetry that results in repetition after every 120-degree rotation

a triad crystal axis

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.