fungusn.[L., a mushroom; perh. akin to a doubtful Gr. sponge, for ; if so, cf. E. sponge.]1. (Bot.) Any one of the Fungi, a large and very complex group of thallophytes of low organization, -- the molds, mildews, rusts, smuts, mushrooms, toadstools, puff balls, and the allies of each. See fungi.()()2. (Med.) A spongy, morbid growth or granulation in animal bodies, as the proud flesh of wounds.(Hoblyn.)