bottom
n//ˈbɑ.təm//botten, underdel, stjärt, bak, rumpa, ända, passiv
The lowest part of anything.
The bed of a body of water.
(clothing) A garment worn to cover the body below the torso.
(euphemism) The buttocks or anus. [1794]
(countable, broadly, by extension) A submissive partner in a sexual relationship.