Definition from Wiktionary, the free dictionary
tetrad (plural tetrads)
- A group of four things.
- (chemistry) A tetravalent atom or radical.
- (biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
- (biology) Group of four haploid and immature pollen grains in tetrahedral fashion produced by meiotic microsporogenesis.