A billabong is a type of oxbow lake. However, friend will hardly ever hear this term supplied to refer to oxbow lakes exterior of Australia.
Billabongs, alongside other oxbow lakes, kind as a flow erodes away at the landscape. Eventually, the flow will adjust its course as it charts the course of the very least resistance from its source to that is outflow.
For a loop of some cool satellite pictures showing just how billabongs and other oxbow lakes form, examine out this video from geography Realm: