circa 1541, in the meaning defined at sense 1
borrowed from Middle French & Latin; Middle French, borrowed from Latin abdōmen "fat underpart of an animal, belly, paunch," of uncertain origin
Note: Often seen as a derivative of abdere, "to hide, conceal," i.e., "that which is hidden," based on a nominal ablaut form *dhoh1- from the root *dheh1- "put." However, Latin abdōmen refers primarily to a body part of animals, and more or less humorously of humans; such usage suggests something prominent rather than something concealed, so the derivation looks somewhat unlikely.
abdomen
nounabdomen
nounabdomen
noun— called also belly