In"board` (?), a. & adv.

1. Naut.

Inside the line of a vessel's bulwarks or hull; the opposite of outboard; as, an inboard cargo; haul the boom inboard.

2. Mech.

From without inward; toward the inside; as, the inboard stroke of a steam engine piston, the inward or return stroke.

 

© Webster 1913.