triad

[trahy-ad, -uh d] /ˈtraɪ æd, -əd/
noun
1.
a group of three, especially of three closely related persons or things.
2.
Chemistry.
  1. an element, atom, or group having a valence of three.
    Compare monad (def 2), dyad (def 3).
  2. a group of three closely related compounds or elements, as isomers or halides.
3.
Music. a chord of three tones, especially one consisting of a given tone with its major or minor third and its perfect, augmented, or diminished fifth.
4.
(initial capital letter) Military. the three categories of strategic-nuclear-weapons delivery systems: bombers, land-based missiles, and missile-firing submarines.
Origin
1540-50; < Latin triad- (stem of trias) < Greek triás See tri-, -ad1
Related forms
triadic, adjective
triadism, noun
Examples from the web for triad
  • All of these paradoxes form a triad that is the way of everything.
  • The second triad harks back to the central principle of scarcity.
  • The major interval contained within the scale generates an implied major triad built on the fourth degree of the scale.
  • It would be the movie's biggest surprise if he weren't the brains behind the triad.
  • Any good screen performer comes to the job equipped with the essential triad of the eye, the smile and the voice.
British Dictionary definitions for triad

triad

/ˈtraɪæd/
noun
1.
a group of three; trio
2.
(chem) an atom, element, group, or ion that has a valency of three
3.
(music) a three-note chord consisting of a note and the third and fifth above it
4.
an aphoristic literary form used in medieval Welsh and Irish literature
5.
the US strategic nuclear force, consisting of intercontinental ballistic missiles, submarine-launched ballistic missiles, and bombers
Derived Forms
triadic, adjective
triadism, noun
Word Origin
C16: from Late Latin trias, from Greek; related to Greek treis three

Triad

/ˈtraɪæd/
noun
1.
any of several Chinese secret societies, esp one involved in criminal activities, such as drug trafficking
Word Origin and History for triad
n.

1540s, "group or set of three," from Late Latin trias (genitive triadis), from Greek trias (genitive triados), from treis "three" (see three). Musical sense of "chord of three notes" is from 1801.

triad in Medicine

triad tri·ad (trī'ād', -əd)
n.

  1. A collection of three things or symptoms having something in common.

  2. The transverse tubule, and the terminal cisternae on each side of it, in a skeletal muscle fiber.

Encyclopedia Article for triad

in chemistry, any of several sets of three chemically similar elements, the atomic weight of one of which is approximately equal to the mean of the atomic weights of the other two. Such triads-including chlorine-bromine-iodine, calcium-strontium-barium, and sulfur-selenium-tellurium-were noted by the German chemist J.W. Dobereiner between 1817 and 1829. The triad was the earliest atomic-weight classification of the elements

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