(Chinese: "knock head"; from kou, "to knock", and tou, "head"; also spelled kowtow or kotow)
In Chinese imperial times, ceremonial abasement, executed by kneeling and placing forehead on the ground to signify humility before a superior. After the Opium War ended in 1842, foreign diplomats from Europe and the U.S. no longer had to perform the koutou to the emperor.