Nautical, outward: noting anything that is without or on or toward the outside of a ship: as, the outboard works; the outboard end of a propeller-shaft. See inboard.Nautical, in a direction laterally away from the center of a ship: the opposite of inboard: as, to move an object outboard.In mech., situated on the outer side or the side farther from the main center. Thus, the outboard bearing of a flywheel on an engine is the bearing which is farther from the crank than the fly-wheel itself, the inboard bearing being between the fly-wheel and the crank.