- (classical studies, usually capitalized) Plato's philosophical system based on skepticism; Plato's followers. [First attested in the mid 16th century.]
- A society of learned people united for the advancement of the arts and sciences, and literature, or some particular art or science. [First attested in the early 17th century.]
"the French Academy; the American Academy of Arts and Sciences; academies of literature and philology."
- A body of established opinion in a particular field, regarded as authoritative.
- (classical studies, usually capitalized) The garden where Plato taught. [First attested around 1350 to 1470.]
- A school or place of training in which some special art is taught. [First attested in the late 16th century.]
"the military academy at West Point; a riding academy; the Academy of Music."
- (with the, without reference to any specific academy) Academia.
- An institution for the study of higher learning; a college or a university; typically a private school. [First attested in the mid 16th century.]
- (obsolete) The knowledge disseminated in an Academy. [Attested from the early 17th century until the mid 18th century.]
- (Britain, education) A school directly funded by central government, independent of local control.