triad

American  

[trahy-ad, -uhd] / 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.

   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. Military. Triad, the three categories of delivery systems for strategic nuclear weapons, namely bombers, land-based missiles, and missile-firing submarines.

   The report says this missile is required in order to sustain an effective air leg of the Triad.

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triad ¹ British  

/ 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

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Triad ² British  

/ ˈtraɪæd /

noun

1. any of several Chinese secret societies, esp one involved in criminal activities, such as drug trafficking

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Other Word Forms

• triadic adjective
• triadism noun

Etymology

Origin of triad

First recorded in 1540–50; from Latin triad- (stem of trias ), from Greek triás; tri-, -ad ¹

Related Words

• triumvirate