fungus /ˈfʌŋ.ɡəs/ noun3 •A eukaryotic organism of the kingdom Fungi typically having chitin cell walls but no chlorophyll or plastids. Fungi may be unicellular or multicellular. •The flesh of such an organism. •(no longer used) A spongy, abnormal excrescence, such as excessive granulation tissue formed in a wound. formsfungi · funguses · fungusses