a simple type of plant that has no leaves or flowers and that grows on plants or other surfaces. mushrooms and mould are both fungi.——朗文当代大辞典

Originally: a mushroom or toadstool. In later use also: any of the organisms of which these are the fruiting bodies (reproductive structures); (more generally) any member of the large biological group (now a kingdom) comprising eukaryotic organisms, including yeasts and moulds as well as mushrooms, which typically have vegetative forms consisting of single cells or of simple multicellular filaments (hyphae) which lack photosynthetic pigments and have chitinous cell walls, and which reproduce by means of sexual and asexual spores. Also (as a mass noun): growths of a fungus or fungi; mould.——牛津当代大辞典  @en