Bum noun - The part of the body upon which someone sits.
Usage example: a woman with a big bum
Bottom is a synonym for bum in butt topic. In some cases you can use "Bottom" instead a noun "Bum", when it comes to topics like over. popular alternative
Bottom noun - The part of the body upon which someone sits.
Usage example: the baby fell backwards onto her bottom
Bum is a synonym for bottom in rear end topic. You can use "Bum" instead a noun "Bottom", if it concerns topics such as buttocks, butt, over. informal substitute
How words are described
Google Ngram Viewer shows how "bum" and "bottom" have occurred on timeline