in•board-out•boardPronunciation: (in'bôrd"out'bôrd", in'bōrd"out'bōrd"), [key]
(of a motorboat) having an inboard engine connected to a maneuverable outboard drive-shaft unit.
an inboard-outboard motor.
a boat equipped with such a motor. Abbr.:
I/O Also called outdrive, stern drive (for defs. 2, 3).
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.