expression, godan verb (-ru)
descend the rapids; shoot the rapids
Used for navigating a boat or raft downstream through rapids. Often implies a skillful or adventurous descent.
船頭が巧みに瀬を下る。
The boatman skillfully descends the rapids.
Compound of 瀬 (rapids, shallows) + を (object marker) + 下る (to go down, descend). The literal meaning is 'to go down the rapids'.