Prímulus, pen. cor. Adiectiuum, diminutiuum Primus. That is at the first or beginning.Primulo diluculo abijsti ad legiones.Plaut.Earelye in the morning so soone as the day brake &c.Primulùm. pen. cor, Aduerb. diminutiuum. Plaut.First: immediately.
Lewis and Short: Latin dictionary
prīmŭlus, a, um, adj. dim. [primus], the first (ante-class.): primulo diluculo, Plaut. Am. 2, 2, 105.—Adv.: prīmŭlum, at first, first (ante-class.), Plaut. Men. 5, 5, 18; 5, 9, 57; Ter. Ad. 3, 1, 2.