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Webster 1913 Edition


Triad

Tri′ad

,
Noun.
[L.
trias
,
-adis
, Gr. [GREEK], [GREEK], fr.[GREEK], [GREEK], three: cf. F.
triade
. See
Three
, and cf.
Trias
,
Trio
.]
1.
A union of three; three objects treated as one; a ternary; a trinity;
as, a
triad
of deities
.
2.
(Mus.)
(a)
A chord of three notes.
(b)
The common chord, consisting of a tone with its third and fifth, with or without the octave.
3.
(Chem.)
An element or radical whose valence is three.
Triads of the Welsh bards
,
poetical histories, in which the facts recorded are grouped by threes, three things or circumstances of a kind being mentioned together.
–
Hindu triad
.

Webster 1828 Edition


Triad

TRI'AD

,
Noun.
[L. trias, from tres, three.] The union of three; three united. In music, the common chord or harmony, consisting of the third, fifth and eighth.