billabong

This indigenous Australian word refers to a body of water that has particular qualities attached to it.

A billabong is often a backwater channel connected with a stream or river. It rises and falls according to the water's flow. It often is the dead end of the river system.

The word arises in an Aboriginal language and was taken into English in the 19th Century. 'Billa' means river and 'bong' means dead.