praevallo
prae-vallo, āre, v. a.,
- to fortify in front (post-class.): pontem, Auct. B. Alex. 19; Claud. ap. I. Cons. Stil. 2, 188.
prae-vāllo, āre, verschanzen, pontem adversus hostem, Auct. b. Alex. 19, 4.
prævallō, (16) āre, tr., palissader, retrancher : B. Alex. 19, 4.