Source : Webster's Revised Unabridged Dictionary (1913)

Outboard \Out"board`\, a. & adv. (Naut.)
   Beyond or outside of the lines of a vessel's bulwarks or
   hull; in a direction from the hull or from the keel; --
   opposed to {inboard}; as, outboard rigging; swing the davits
   outboard.

Source : WordNet®

outboard
     adj : located away from the midline of a vessel or aircraft; "the
           outboard section of a wing"; "outboard rigging" [ant: {inboard}]

outboard
     n 1: a motorboat with an outboard motor [syn: {outboard motorboat}]
     2: internal-combustion engine that mounts at stern of small
        boat [syn: {outboard motor}]