noun, plural: tetrads
(1) (cell biology) A group of four closely associated chromatids of a homologous pair formed by synapsis.
(2) (genetics) The four spores of yeast.
(3) (chemistry) A tetravalent atom; a quadrivalent element.
(4) A group consisting of four; the number four.
In cell biology, a tetrad pertains to the structure formed by the synapsis of homologous chromosomes during the prophase I of meiosis.
Word origin: Greek tetras, tetrad-