Fungus
Part of speech: noun
Definition: Any member of the kingdom Fungi; a eukaryotic organism typically having chitin cell walls but no chlorophyll or plastids. Fungi may be unicellular or multicellular.
Mushroom
Part of speech: noun
Definition: Any of the fleshy fruiting bodies of fungi typically produced above ground on soil or on their food sources (such as decaying wood).A fungus producing such fruiting bodies.
Part of speech: adjective
Definition: Containing or being made of mushrooms.Resembling a mushroom by shape or appearance.
Part of speech: verb
Definition: To grow quickly to a large size.To gather mushrooms.