Lewis & Short

chrīa, ae, f., = χρεία, in rhetoric, a sentence proposed as a theme for rhetorical exercise, with its logical development, Quint. 1, 9, 3 sq.; 1, 9, 4 sq.; 2, 4, 26 Spald.; Sen. Ep. 33, 6; Diom. p. 289 P.