long course; 50-meter pool lane
Used in competitive swimming to refer to a lane in a 50-meter pool, as opposed to a 25-meter short course (短水路).
See also: 短水路
This competition is held in a long course (50-meter pool).
It is said that long course records are harder to achieve than short course records.
Compound of 長 (long) and 水路 (waterway, channel), referring to a long swimming lane.