Cap
A cap is a tiny green cover which loosens, then falls off exposing the pinhead-size ovary and releasing the pollinating anthers of an individual grape flower. When the cap falls off and anthers extend, the flower is said to be in bloom.
Cap
When used in terms of vinification, the cap is the mass of floating solids (skins and bits of stem) in a tank of fermenting red wine. It binds together forming a thick mat which must be wetted at least daily during fermentation in order to extract the color and flavor.