▸ preposition on or into (a ship, aircraft, train, or other vehicle):
I climbed aboard the yacht
the suspects had recently arrived in Italy aboard a cargo ship.
▪ on or on to (a horse):
he emulated his father's Aintree win with a victory of his own aboard Bobbyjo in 1999.
▸ adverb on or into a ship, aircraft, train, or other vehicle:
the plane crashed, killing all 158 people aboard
welcome aboard!
she came aboard as executive vice president of membership and operations in December 2014 figurative.
▪ on or on to a horse:
with Richard Migliore aboard, he won the cup at a gallop.
▪ Baseball on base as a runner:
they put their first batter aboard
he was aboard for the homers by Grissom and Alfonzo.