secondary armament; secondary battery; secondary gun
Technical naval term for the smaller-caliber guns on a warship, distinct from the main battery.
The secondary guns of a battleship have a smaller caliber than the main guns.
主砲 is a warship's primary, largest guns, while 副砲 refers to its secondary, smaller guns.
Compound of 副 (ふく, 'secondary, auxiliary') and 砲 (ほう, 'gun, cannon').