sŭperventus, ūs, m. [supervenio], a coming up or upon, an arrival (post-Aug.).
I In gen., Plin. 7, 15, 13, § 64; Tac. H. 2, 54.—
II In partic., in milit. lang., an attack , Veg. Mil. 3, 8; 3, 22.
(superventus, ūs) m a coming up, arrival. —Only abl: superventu quartae decimae legione...
An Elementary Latin Dictionary