- Inside the line of a vessel's bulwarks or hull; the
opposite of outboard; as, an inboard cargo; haul the boom inboard. - From without inward; toward the inside; as, the
inboard stroke of a steam engine piston, the inward or return stroke.
Meaning of 'inboard' (Princeton's WordNet)
1 . inboard
[ a]
Meaning (1): - located within the hull or nearest the midline of a vessel or aircraft