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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.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


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]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(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]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
Dyad Leadership and Clinical Integration: Driving Change, Aligning Strategies
In 2016, Hoffman was named president and clinical dyad leader of St.
Dyad Productions performer Rebecca Vaughan and writer-director Elton Townend Jones explore what it means to find our place in the world whilst remaining true to who we are.
Tony Nguyen is vice president of corporate relations for Dyad Labs in Salt Lake City, UT.
Chude-Sokei explores the race/technology dyad through a Caribbean-influenced critical practice demonstrated by such scholars as Aime Cesaire, Wilson Harris, Edouard Glissant, and Sylvia Wynter, among others.
In a retributive exchange, the equivalence ratio between labor and earnings is asymmetric when earnings for placing pieces in one's own puzzle may not be the same for each member of the dyad, or may be unequal when earnings for placing pieces of the peer's puzzle are not the same for each member of the dyad (Ribes et al., 2003; Ribes, Rangel, Magana, Lopez, & Zaragoza, 2005).
For our study, the effects of both conditions for each participant dyad were examined for three outcomes: adolescent anxiety behavior (during transition and during grocery store shopping); social interaction (during grocery store shopping); and self-reported parental stress (following transition and following grocery store shopping).
The organizations began dyad research last year when they brought together CMO and CNO executives for eight dyad pairings and have continued with roundtables, interviews, presentations, panels, articles and podcasts.
Our modeling suggests that a triad is better than a dyad, at least of similar or lesser cost, according to most metrics.
Modules which compose most planar constrained mechanisms can be considered as three basic types; namely, a dyad, a crank rocker, and a slider.