gun time
n.— «A similar issue arose at the Chicago Marathon two weeks ago, when Wesley Korir of Kenya finished fourth, despite starting five minutes after the elite runners. Like O’Connell, his time was clear because of the electronic timing chips that are worn on each runner’s shoe. And, like O’Connell, his chip time was different from what is known as the gun time, measured from the moment of the starting signal to the instant the runner crosses the line, since he ran well behind the elites with the main pack.» —“A Marathon Oddity Leads to Two First-Place Finishers” by Joshua Robinson New York Times Oct. 23, 2008. (source: Double-Tongued Dictionary)
Further reading
Linda in Salisbury, North Carolina, wonders why boxing is called the sweet science, since there’s nothing obviously sweet about a bruising sport. This term took hold among British sportswriters in the early 19th century as promoters tried to frame...
A man who grew up in Nairobi, Kenya, says that when he and his friends were playing a game of tag and wanted to take a break they would call “Pax!” This Latin word for peace used in this way is what’s called a truce term. Other non-obvious examples...