artillery

Artillery comes from Middle English artillerie, borrowed from Old French artillerie, meaning a collection of military engines like crossbows and lances. That French word traces to artillier, 'to equip or provide with contraptions,' itself an alteration of atiller, 'to arrange or put on armor,' shaped by the word art and ultimately rooted in Latin aptō, 'to make capable.'

The word started out covering any gear used to arrange or equip oneself for war, especially armor, before narrowing to describe the engines and weapons of battle themselves.

It shares a root with Latin aptō, 'to make capable' — the same idea behind English 'apt,' something suited or fitted to a purpose.