On a ship (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">on a ship</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for aboard that I've seen before include "On vessel or vehicle" , "Embarked on (a ship)" , "on a train, perhaps" , "on a plane, perhaps" , "On (a ship, train, etc)" .)