a hormone, CHNOS, of the posterior pituitary gland, that stimulates contractions in the smooth muscle of the uterus and facilitates the secretion of milk
Origin:
< oxytocic + -in
See oxytocin in American Heritage Dictionary 4
noun
A short polypeptide hormone, C43H66N12O12S2, released from the posterior lobe of the pituitary gland, that stimulates the contraction of smooth muscle of the uterus during labor and facilitates ejection of milk from the breast during nursing.