Definition of tetrads:
(n) :
A group of four things.
(n) :
(music) A chord comprised of four notes; a tetrachord.
(n) :
(biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
(n) :
(biology) A group of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic microsporogenesis.
(n) :
(mathematics) A group of four basis vectors for a four-dimensional manifold in differential geometry.
(n) :
(chemistry) A tetravalent atom or radical.