The Couple name of Jaejoong and Yunho of the korean boyband DBSK.
The word is a combination of the 'Jae' in (Jae)joong and the 'ho' in Yun(ho).
This pairing differs from Yunjae in that the person who's at the front of the name is dominant. In Jaeho, Jaejoong the dominant partner and Yunho is the more submissive partner.
Did you read that new Jaeho fanfic on LJ? Jaejoong was so manly! O.O