What is the X in X-mas?
"female organ of a flower," 1718, from French pistil, from Modern Latin pistillum "a pistil," so called from resemblance to a pestle, from Latin pistillum "pestle" (see pestle). Related: Pistillary; pistillaceous; pistillate; pistilline.
One of the female reproductive organs of a flower, consisting of a single carpel or of several carpels fused together. A flower may have one pistil or more than one, though some flowers lack pistils and bear only the male reproductive organs known as stamens. See more at carpel, flower.