quantum chromodynamics: a theory of strong interactions between elementary particles (including the interaction that binds protons and neutrons in the nucleus); it assumes that strongly interacting particles (hadrons) are made of quarks and that gluons bind the quarks together
secretory phase: the second half of the menstrual cycle after ovulation; the corpus luteum secretes progesterone which prepares the endometrium for the implantation of an embryo; if fertilization does not occur then menstrual flow begins