n. (pl. medusae or medusas)
1. a jellyfish.
2 a free-swimming form of any coelenterate, having tentacles round the edge of a usu. umbrella-shaped jelly-like body, e.g. a jellyfish.
Derivatives:
medusan adj.
Etymology: L f. Gk Medousa, name of a Gorgon with snakes instead of hair