Gymnasium (and variations of the word) is a term in various European languages for a secondary school that prepares students for higher education at a university. It is comparable to the US English term preparatory high school. Before the 20th century, the gymnasium system was a widespread feature of educational systems throughout many European countries.

The word γυμνάσιον (gumnásion), from Greek γυμνός (gumnós) 'naked' or 'nude', was first used in Ancient Greece, in the sense of a place for both physical and intellectual education of young men. The latter meaning of a place of intellectual education persisted in many European languages (including Albanian, Bulgarian, Estonian, Greek, German, Hungarian, the Scandinavian languages, Dutch, Polish, Czech, Serbo-Croatian, Macedonian, Slovak, Slovenian and Russian), whereas in other languages, like English (gymnasium, gym) and Spanish (gimnasio), the former meaning of a place for physical education was retained.