Inboard /(?)/

In·board

Inboard

a. & adv.
  1. Inside the line of a vessel's bulwarks or hull; the opposite of outboard; as, an inboard engine; an inboard cargo; haul the boom inboard. (Naut.)
  2. From without inward; toward the inside; as, the inboard stroke of a steam engine piston, the inward or return stroke. (Mech.)