Lewis & Short

histrĭōnĭcus, a, um, adj. [histrio], of or belonging to a player, histrionic (post-class.): operae, Dig. 32, 1, 73: gestus, Amm. 14, 6, 18.
Subst.: histrĭōnĭca, ae, f., the player’s art, Lampr. Heliog. 12, 1.