inboard

UK: /ˈɪnˌbɔːd/ US: /ˈɪnˌbɔrd/ ,(in′bôrd′, -bōrd′)

WordReference Random House Learner's Dictionary of American English © 2025

in•board /ˈɪnˌbɔrd/   adj. 

1. Naval Terms, Nautical located inside a hull or aircraft.
2. Naval Terms located nearer the center, as of an airplane.

adv. 

3. Naval Terms, Nautical inside or toward the center of a machine, etc.

WordReference Random House Unabridged Dictionary of American English © 2025

in•board  (in′bôrd′, -bōrd′), adj. 

1. Naval Terms located nearer the longitudinal axis or center, as of an airplane:
   the inboard section of a wing.
2. Naval Terms, Nautical located inside a hull or aircraft:
   a motorboat with an inboard engine.
3. Naval Terms, Nautical (of a motorboat) having the motor inboard.

adv. 

4. Naval Terms, Nautical inside or toward the longitudinal axis or center of a hull, aircraft, machine, etc. Cf. outboard (def. 4).

n. 

5. Nautical, Naval Terms an inboard motor.
6. Nautical, Naval Terms a boat equipped with an inboard motor.

• origin, originally phrase in board 1840–50

Collins Concise English Dictionary © HarperCollins Publishers::

inboard / ˈɪnˌbɔːd/ adjective

1. (esp of a boat's motor or engine) situated within the hull
   Compare outboard1
2. situated between the wing tip of an aircraft and its fuselage: an inboard engine

adverb

1. towards the centre line of or within a vessel, aircraft, etc