'agaricaceous' originates from the Latin word 'agaricum', which referred to a type of fungus, combined with the suffix '-aceous', indicating belonging to or having the nature of.

'Agaricum' was used in Latin to describe a type of fungus, and the term evolved into 'agaricaceous' in modern English to describe fungi belonging to the Agaricaceae family.

Initially, it referred specifically to a type of fungus, but over time it evolved to describe the entire family of fungi, Agaricaceae.