dyad

American  

[dahy-ad] / ˈdaɪ æd /

Sometimes diad

noun

1. a group of two; couple; pair.

2. Biology.

   1. a secondary morphological unit, consisting of two monads.

      a chromosome dyad.

   2. the double chromosomes resulting from the separation of the four chromatids of a tetrad.

3. Chemistry. an element, atom, or group having a valence of two.

4. Mathematics. two vectors with no symbol connecting them, usually considered as an operator.

5. Sociology.

   1. two persons involved in an ongoing relationship or interaction.

   2. the relationship or interaction itself.

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adjective

1. of two parts; dyadic.

dyad British  

/ ˈdaɪæd /

noun

1. maths an operator that is the unspecified product of two vectors. It can operate on a vector to produce either a scalar or vector product

2. an atom or group that has a valency of two

3. a group of two; couple

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Etymology

Origin of dyad

First recorded in 1665–75; from Greek dyad- (stem of dyás ) “pair,” equivalent to dý(o) “two” + -ad- noun suffix; see origin at two, -ad ¹

Explanation

A dyad is a group of two things or two people. If you have a dyad of brothers, there are two of them. While you can use the noun dyad to mean "pair," "couple," or "duo," it's much more common to find the word used in a technical way. Sociologists, for example, use dyad to refer to social groups that consist of only two people, like a brother-sister dyad or a mother-child dyad. The word stems from the Greek dyas, "the number two," or "a group of two," from duo, "two."

Example Sentences

In every instance, it’s the devouring twin who has returned, not the bright Indo-Greek dyad.

From New York Times • Feb. 12, 2024

Li tells me the characters came to her together, “yin and yang,” only whole as a dyad.

From Los Angeles Times • Sep. 20, 2022

The failure of the psychotherapeutic process is located at its epicenter: the power disparity in the therapeutic dyad.

From Scientific American • Jul. 12, 2020

Despite this, Salon's Matthew Rozsa found the coda "extremely satisfying," even as fans decried the sidelining of Rose Tico or tried to puzzle out the ins and outs of the Force dyad.

From Salon • May 1, 2020

Meanwhile, Jaime and Nicolas were growing up apart from the feminine dyad, adhering to the then common belief that “we have to become men.”

From "The House of the Spirits: A Novel" by Isabel Allende

Related Words

• combination
• couple
• duo
• match
• team
• two