1. aboard, on board

on a ship, train, plane or other vehicle

• on board

2. aboard, on base

on first or second or third base

Example Sentences:
'Their second homer with Bob Allison aboard'

• on base

3. aboard, alongside

side by side

Example Sentences:
'anchored close aboard another ship'

• alongside

4. aboard

part of a group

Example Sentences:
'Bill's been aboard for three years now'