gymnasium (n.)

1590s, "place of exercise," from Latin gymnasium "school for gymnastics," from Greek gymnasion "public place where athletic exercises are practiced; gymnastics school," in plural, "bodily exercises," from gymnazein "to exercise or train," literally or figuratively, literally "to train naked," from gymnos "naked," from a metathesis of PIE *nogw-mo-, suffixed form of *nogw- "naked" (see naked).

A feature of all ancient Greek communities, at first it was merely an open space, later with extensive facilities and including training for the mind as well as the body. Hence its use in German from 15c. as a name for "high school" (more or less paralleling a sense also in Latin); in English it has remained purely athletic. For the "continental high school sense," English in 19c. sometimes used gymnastical as an adjective, gymnasiast for a student.

updated on April 30, 2015

Definitions of gymnasium from WordNet
gymnasium (n.)
athletic facility equipped for sports or physical training;
Synonyms: gym
Gymnasium (n.)
a school for students intermediate between elementary school and college; usually grades 9 to 12;
Synonyms: secondary school / lyceum / lycee / middle school
From, not affiliated with etymonline.