Oxbow

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.

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

the land inside an oxbow bend in a river