n.
Pronunciation: ' te- ˌ trad
Function: noun
Etymology: Greek tetrad-, tetras, from tetra-
Date: 1653
: a group or arrangement of four: as a : a group of four cells produced by the successive divisions of a mother cell <a tetrad of spores> b : a group of four synapsed chromatids that become visibly evident in the pachytene stage of meiotic prophase
– te · trad · ic \ te- ' tra-dik \ adjective