|1.||[ adverb ] on a ship, train, plane or other vehicle|
|2.||[ pronoun ] preposition, onto the ship|
|3.||[ adverb ] (baseball) on first or second or third base|
"Their second homer with Bob Allison aboard"
|4.||[ adverb ] side by side|
"anchored close aboard another ship"
|5.||[ adverb ] part of a group|
"Bill's been aboard for three years now"