The Greek word is γυμνάσιον (*gymnasion*), from γυμνός (*gymnos*, "naked"). The institution also served as a center for military training and cultural education. Greek law regulated adult men pursuing boys sexually at the gymnasium (Aeschines, *Against Timarchus* 10-12, 138-139; see also Scanlon, *Eros and Greek Athletics*, Oxford, 2002). The author's condemnation here echoes 2 Kings 17:7-17 — language reserved for child sacrifice and national apostasy. See The Greek Gymnasium: What 1 Maccabees 1:14 Actually Describes for the full evidence.