(nautical) An alert aboard a warship, summoning the crew to man all weapons and all stations.

(idiomatic) A challenge with the odds of success stacked strongly against.

(Britain, informal) A bus that is used as a mobile office and publicity centre by a politician or party during the run-up to an election

(intransitive) To fight or compete against one or more opponents, in order to decide a winner.

(intransitive) To engage in a fight; to battle.

plural of battle-ax

(military, army) The notional line on either side of which opposing forces are arrayed, and at which they meet in battle; a fortified line, short of the line where battle is expected, and behind which forces are arrayed; a forward line of infantry or other force, prepared for battle.

(archaic) Complete set of clothes used for body protection in battle, armour

plural of battle cry

(military) An exclamation troops yell out when going to war or battle. / (by extension) A strong motto or purpose statement, especially in regards to winning a goal in sports, games or work.