Why does Logan call Rory 'Ace'(or am i hearing it wrong,is he calling her something else,lol)?

I was just wondering b/c i saw a rerund of "Say Something" on ABCFamily(its now one of my fav eps)and i noticed that besides,"Kiddo" Logan continuously calls Rory "Ace".one of the many things i didnt like about him in this ep,not why its my fav..lol.well,if anyone has an answer i'd like to know and thnx and advace:)