- two units regarded as one; pair
- Biol. a double chromosome resulting from the division of a tetrad in meiosis; half of a tetrad
- Chem. an atom, element, or radical with a valence of two
- Sociology two persons in a continuing relationship involving interaction
Origin of dyadLate Latin dyas (gen. dyadis) from Classical Greek from dyo, two
- Two individuals or units regarded as a pair: the mother-daughter dyad.
- Biology One pair of homologous chromosomes resulting from the division of a tetrad during meiosis.
- 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 (2 a + 3 b + c ) w .b. A tensor formed from a vector in a vector space and a linear functional on that vector space.
Origin of dyadFrom Greek duas duad- from duo two ; see dwo- in Indo-European roots.
From Ancient Greek δύας (dýas), δύαδ- (dýad-) from Ancient Greek δύο (dýo) from Ancient Greek δύο (duo), from Proto-Indo-European *duwó,*duwéh₃ (*dwóh₁). “dyad” in The American Heritage® Dictionary of the English Language, Fourth Edition, Houghton Mifflin Company, 2000.