Buttock and Rear end

Buttock noun - Either of the two large fleshy masses of muscular tissue that form the human rump.

Rear end and buttock are semantically related. in bottom topic. In some cases you can use "Rear end" instead a noun "Buttock".

Rear end noun - The part of the body upon which someone sits.

Buttock and rear end are semantically related. Sometimes you can replace term "Buttock" with "Rear end", this terms are similar.