dyad

[dahy-ad] /ˈdaɪ æd/
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.
Compare monad, triad (def 2a).
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.
adjective
6.
of two parts; dyadic.
Origin
1665-75; < Greek dyad- (stem of dyás) pair, equivalent to dý(o) two + -ad- -ad1
Examples from the web for dyad
  • Make the case that a never-ceasing dyad of enmity helps no one.
  • For promotion and tenure, mentoring is essential, but the dyad need not always be a senior scholar tutoring a junior one.
British Dictionary definitions for dyad

dyad

/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
Word Origin
C17: from Late Latin dyas, from Greek duas two, a pair
dyad in Medicine

dyad dy·ad (dī'ād', -əd)
n.

  1. Two individuals or units regarded as a pair, such as a mother and a daughter.

  2. A divalent atom or radical.

  3. One pair of homologous chromosomes resulting from the division of a tetrad during meiosis.