dyad

English

Etymology

From Ancient Greek δυάς (duás), δυάδ- (duád-) from δύο (dúo, “two”), from Proto-Indo-European *duwó, *duwéh₃ (*dwóh₁).[1] The mathematics sense was coined by Josiah Willard Gibbs in 1884 in the second half of his book Elements of Vector Analysis.

Pronunciation

IPA^(key): /ˈdaɪ.æd/
Rhymes: -aɪæd
Homophone: diad

Noun

dyad (plural dyads)

A set of two elements treated as one; a pair.
Synonyms: couple, duad; see also Thesaurus:duo
- 1908, W. D. Ross, Metaphysics Book I, translation of original by Aristotle:
  […] positing a dyad and constructing the infinite out of great and small, instead of treating the infinite as one, is peculiar to him; […]
- 2019 January 29, Tom Bissell, “An Anti-Facebook Manifesto”, in New York Times‎:
  McNamee describes their grip on the company as “the most centralized decision-making structure I have ever encountered in a large company.” Their power dyad is possible only because Facebook’s “core platform,” as McNamee puts it, is relatively simple: It “consists of a product and a monetization scheme.”
(sociology) Two persons in an ongoing relationship; dyadic relationship.
- 2003, Debra Lieberman; John Tooby; Leda Cosmides, The evolution of human incest avoidance mechanisms […] ‎, page 20:
  For each individual in a specific dyad (i.e., mother-offspring, offspring-father, sibling-sibling), […]
(sociology) The relationship or interaction itself in reference to a couple.
(music) Any set of two different pitch classes.
(chemistry) An element, atom, or radical having a valence of or combining power of two.
(biology) A chromosome structure, usually X- or V-shaped, consisting of two condensed sister chromatids joined by a centromere.
(biology) A secondary unit of organisation consisting of an aggregate of monads.
(mathematics) A tensor of order two and rank one.

Coordinate terms

(group) monad, duad/dyad, triad, tetrad, pentad, hexad, hebdomad/heptad, ogdoad/octad, ennead/nonad, decad/decade, hendecad, dodecad/duodecade, chiliad

Derived terms

dyadic
dyadwise
dyadically
dyadism
pseudodyad

Translations

set of two different elements

Bulgarian: двойка (bg) f (dvojka), чифт (bg) m (čift)
Finnish: pari (fi)
French: duo (fr) m
Malay: bendua, diad
Polish: diada (pl), para (pl)
Portuguese: díade (pt) f
Russian: диада (ru) (diada), пара (ru) (para), двойка (ru) (dvojka)

(music) any set of two different pitch classes

Finnish: dyadi
Japanese: 二和音 (ni-waon)
Portuguese: díade (pt) f

pair of things standing in particular relation

Bulgarian: чифт (bg) m (čift)
Finnish: pari (fi), kaksikko (fi)

(chemistry) element, atom, etc., having a valence of two

Bulgarian: двувалентен елемент m (dvuvalenten element)
Finnish: kahdenarvoinen (adjective)

References

“dyad”, in The American Heritage Dictionary of the English Language, 4th edition, Boston, Mass.: Houghton Mifflin, 2000, →ISBN.

Anagrams

Addy, D-Day, Dady, addy

[1] “dyad”, in The American Heritage Dictionary of the English Language, 4th edition, Boston, Mass.: Houghton Mifflin, 2000, →ISBN.