On - Crossword Clue, Answer and Explanation

(Other definitions for aboard that I've seen before include "On an aircraft" , "in a car" , "Joined for mutual benefit" , "'On a ship or train, say (6)'" , "On ship or plane - not on land" .)

I've seen this clue in the Newsday and The New York Times.

'on' is the definition. (over can mean on top of) This is all the clue.

(Other definitions for over that I've seen before include "Action far more drastic than necessary" , "bowling unit" , "Higher than; finished" , "balls > left" , "See 18" .)

I've seen this clue in The Star Tribune, the King Feature Syndicate, the Universal, the USA Today, The Times, The Telegraph, the Sydney Morning Herald, The New York Times, the LA Times and The Guardian.

(Other definitions for upon that I've seen before include "Lying on top of" , "Atop" , "Children's tales may begin ` `Once .... a time' '" , ".... my word! I'm shocked" , "Preposition" .)

I've seen this clue in The Star Tribune, the King Feature Syndicate, the Universal, the USA Today, The Times, The Telegraph, the Sydney Morning Herald, The New York Times, the LA Times and The Guardian.

On (4)