ox·bow /ˈɑksˌbo/
  U字形彎曲;牛軛U字形部份
  Ox·bow n. A frame of wood, bent into the shape of the letter U, and embracing an ox's neck as a kind of collar, the upper ends passing through the bar of the yoke; also, anything so shaped, as a bend in a river.
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  oxbow
       n 1: the land inside an oxbow bend in a river
       2: a U-shaped curve in a stream
       3: a wooden framework bent in the shape of a U; its upper ends
          are attached to the horizontal yoke and the loop goes
          around the neck of an ox