Also 1-on-1, one on one, etc.
1. Competition between an individual player and an individual opponent, as opposed to team play, scotch doubles and other multi-player variants.
2. A team play format in which an individual player from the home team plays a race against an individual player from the visiting team, and then is finished for that match. (Same as match play, definition 2.) Several large leagues use this format, including APA/CPA and USAPL. (Contrast round robin.)