moenia, ium, n. plural: defensive walls, city walls, city enclosed by walls

Aeneid, 1.7, altae moenia Romae (the walls of high Rome), cf. munio, ire, to build a wall, to erect or raise fortifications. Eng., munition, war materiel, especially weapons and ammunition.
George Chapman, trans. of The Odysseys of Homer, 6.408-19:

On whose either side/ A fair port stands, to which is nothing wide/ An enterer's passage; on whose both hands ride/ Ships in fair harbours; which once past, you win/The goodly market-place (that circles in/ A fane to Neptune, built of curious stone,/ And passing ample) where munition,/ Gables, and masts, men make, and polish'd oars;/ For the Phaeacians are not conquerors/By bows nor quivers; oars, masts, ships they are/ With which they plough the sea, and wage their war.