1. (

• aboard ,
• on_board

) on a ship, train, plane or other vehicle ;

2. (

• aboard

) on first or second or third base; "Their second homer with Bob Allison aboard" ;

3. (

• aboard ,
• alongside

) side by side; "anchored close aboard another ship" ;

4. (

• aboard ,

) part of a group; "Bill's been aboard for three years now" ;