medusoid(n = noun.animal) medusa, medusan - one of two forms that coelenterates take: it is the free-swimming sexual phase in the life cycle of a coelenterate; in this phase it has a gelatinous umbrella-shaped body and tentacles;
Like a medusa; having the fundamental structure of a medusa, but without a locomotive disk; -- said of the sessile gonophores of hydroids. [1913 Webster]