used in various place names, such as Lingtou 坽头 líng​tóu or Lingkoutan 坽口滩 líng​kǒu​tān

entrance, exit, or pass, such as a mountain pass, port, or gate in the Great Wall

(bound form) a place in a river where the water is shallow and the current is swift due to rocks or sandbars; rapids; shoal