tri·​ad | \ ˈtrī-ˌad How to pronounce triad (audio) also -əd \

Definition of triad

1 : a union or group of three : trinity
2 : a chord of three tones consisting of a root with its third and fifth and constituting the harmonic basis of tonal music

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Other Words from triad

triadic \ trī-​ˈa-​dik How to pronounce triad (audio) \ adjective
triadically \ trī-​ˈa-​di-​k(ə-​)lē How to pronounce triad (audio) \ adverb

Did You Know?

The best-known type of triad is a type of musical chord consisting of three notes. A D-major triad is made up of the notes D, F-sharp, and A; an F-minor triad is made up of F, A-flat, and C; and so on. Major and minor triads form the basis of tonal music, and songs and other pieces usually end with a triadic harmony. In medicine, a triad is a set of three symptoms that go together. The Chinese criminal organizations called triads got their name from the triangular symbol that they used back when they began, centuries ago, as patriotic organizations. Today, with over 100,000 members, the triads operate in the U.S., Canada, and many other countries.

Examples of triad in a Sentence

a triad of candlesticks on the mantel
Recent Examples on the Web The triad of neurological symptoms has been so consuming that the threat of the coronavirus itself blipped almost entirely off Diana’s radar. Katherine J. Wu, The Atlantic, "Surviving the Pandemic as a Kid With Chronic Illness," 27 Apr. 2021 This time, military leaders and nuclear security experts warn there is no more room for delay if the United States is to maintain all three legs of its nuclear triad and catch up to the investments made by peer adversaries. Abraham Mahshie, Washington Examiner, "Congress fights over liberal cuts to America’s nuclear arsenal," 29 Mar. 2021 Young people with moderate-to-severe symptoms should undergo a triad of tests — an echocardiogram, an EKG and a blood test. Josh Peter, USA TODAY, "'It saved my kid's life:' Why aren't all college athletes with COVID-19 getting MRI exams?," 31 Dec. 2020 The symptoms made up two-thirds of a triad that Hoffman had often observed and treated in his 20 years in the E.R. but had never seen quite so clearly. New York Times, "Her Legs Would Barely Follow Her Brain. Then She Saw Double.," 3 Dec. 2020 Vitruvius is famous for articulating a triad of core qualities that each building must have: firmitas, utilitas, venustas. Daisy Alioto, Longreads, "House of the Century," 10 Aug. 2020 The chaotic triad of bumbling fairies is seemingly unable to rise to the task of raising Aurora, so Maleficent does it from afar. Jeanna Kadlec, Longreads, "Deconstructing Disney: Motherhood and the Taming of Maleficent," 8 Oct. 2020 In fact, questions about whether the triad of symptoms found in Effie’s scans are caused by abuse or other innocent events have seen medics, scientists and the police go to war. Catherine Cusick, Longreads, "8 Longreads by Will Storr on the Science of Storytelling," 10 Aug. 2020 The Military Power Report also noted that China is developing its own nuclear triad. Abraham Mahshie, Washington Examiner, "China's nuclear arms buildup 'inconsistent' with no-first-use policy, StratCom chief says," 14 Sep. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'triad.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of triad

1546, in the meaning defined at sense 1

History and Etymology for triad

Latin triad-, trias, from Greek, from treis three

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Statistics for triad

Last Updated

7 May 2021

Cite this Entry

“Triad.” Dictionary, Merriam-Webster, Accessed 7 May. 2021.

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More Definitions for triad



English Language Learners Definition of triad

: a group of three usually related people or things
: a secret Chinese criminal organization


tri·​ad | \ ˈtrī-ˌad How to pronounce triad (audio) \

Kids Definition of triad

: a chord made up usually of the first, third, and fifth notes of a scale


tri·​ad | \ ˈtrī-ˌad also -əd \

Medical Definition of triad

1 : a union or group of three a triad of symptoms
2 : a trivalent element, atom, or radical

Other Words from triad

triadic \ trī-​ˈad-​ik How to pronounce triad (audio) \ adjective

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Comments on triad

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