What does the prefix com mean in combat?

The prefix "com" in "combat" doesn't actually stand for anything specific. It's part of the word's origin.

Combat comes from the Old French word "combattre," which itself comes from the Latin "combattere." This word is formed from the prefix "com-" (meaning "with" or "together") and the verb "battere" (meaning "to beat").

Therefore, the "com" in "combat" simply means "together," reflecting the idea of two or more parties engaging in a fight.