munition

From Latin mūnitiō, meaning "a defence, fortification," via French munition. Mūnitiō comes from the verb mūnīre, "to fortify or defend with a wall," which itself traces to moenia, "city walls, defensive walls."

The word started out describing the act or state of fortifying a place, tied directly to walls and defenses, before narrowing to the supplies and equipment used in war.

It shares its root, mūnīre, with the sense of walling and defending that lies behind the word's earliest meaning, though no other English cognate is given in the facts.