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 (dī′ăd′, -əd)
1. Two individuals or units regarded as a pair: the mother-daughter dyad.
2. Biology One pair of homologous chromosomes resulting from the division of a tetrad during meiosis.
3. Mathematics
a. A function that draws a correspondence from any vector u to the vector (v·u)w and is denoted vw, where v and w are a fixed pair of vectors and v·u is the scalar product of v and u. For example, if v = (2,3,1), w = (0,-1,4), and u = (a,b,c), then the dyad vw draws a correspondence from u to (2a + 3b + c)w.
b. A tensor formed from a vector in a vector space and a linear functional on that vector space.
Made up of two units.

[From Greek duas, duad-, from duo, two; see dwo- in Indo-European roots.]


1. (Mathematics) 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. (Chemistry) an atom or group that has a valency of two
3. a group of two; couple
[C17: from Late Latin dyas, from Greek duas two, a pair]


(ˈdaɪ æd)

1. a group of two; couple; pair.
2. the double chromosomes resulting from the separation of the four chromatids of a tetrad.
3. an element, atom, or group having a valence of two.
4. Math. two vectors with no symbol connecting them, usu. considered as an operator.
a. two people involved in an ongoing relationship or interaction.
b. the relationship or interaction itself.
6. of two parts; dyadic.
[1665–75; < Greek dyad-, s. of dyás pair <dý(o) two]
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.dyad - two items of the same kinddyad - two items of the same kind    
fellow, mate - one of a pair; "he lost the mate to his shoe"; "one eye was blue but its fellow was brown"
2, II, two, deuce - the cardinal number that is the sum of one and one or a numeral representing this number
doubleton - (bridge) a pair of playing cards that are the only cards in their suit in the hand dealt to a player
References in periodicals archive ?
As identified by Frampton in his essay, 'On Reading the Elemental', the ubiquitous cube versus courtyard dyad invariably crops up, and this once again emerges as the basis behind the rationale of the Benetton pre-school in Treviso.
Switching one member in each dyad to the other group for the second phase of the assignment created new dyads.
Students were also advised that, through the use of these forms, they would learn how to gather specific information from the dyad.
In our first hypothetical example, a school counselor and a classroom teacher used a multicomponent intervention to increase dyad and group play, and decrease isolate activities, of a withdrawn and socially inept third grader, Kainoa, during recess periods.
He describes an early case failure and what he learned, the insights of an analyst, an assessment of whether self-analysis is possible, and reflections on transference, the unconscious, and the limits of the analytic dyad.
Fish's insistence, however, upon reading the three women as "counter-agents" rebellious to normative categories of womanhood, discourses of domesticity, and literary traditions often fixes her discussions within a dyad of complicity or resistance.
Panopticon is a concept record based on the French philosopher Michel Foucault's theory of the panopticon as a machine to disassociate the seen-being-seen dyad.
This paper defines the terms bully and bullying and discusses the bully/disability dyad.
The result is a program that is moving away from a mom-child dyad focus toward a father-mother-child triad focus, which acknowledges the key contribution that fathers can make in their children's lives.
Related is the identification of women who were not tribades as "chaste femmes," a phrase that invokes the feminine half of the modern butch/femme dyad.
Separate factorial ANOVAs were used to compare speaking-turn frequencies and durations, the vocal-state frequencies and durations of the pairs of friends and acquaintances, and their gender and dyad gender (whether same-gender or cross-gender).