Lewis & Short

mĕthŏdĭum, ii, n., = μεθόδιον, a witty conceit, a jest, joke (post-Aug.): Trimalchio ejusmodi methodio laetus, Carpe, inquit, etc. (al. metōdīum, i. e. μετωδεῖον, an inserted song), Petr. 36, 5.