Triple sec
Triple sec is a strong, clear orange-flavored liqueur. It is sweet, but not cloying.
In addition to the generic brand Triple Sec, Curaçao, Cointreau, and Grand Marnier are also triple secs.
While triple sec usually would mean "triple dry", it here mans "triple distilled".
One generic brand is De Kuyper Triple Sec (image of bottle to the left).