postérieur

/pɔs.te.ʁjœʁ/
1.
nounmasculine

backside

buttocks

rear end

Il est tombé sur son postérieur en plein milieu du salon.

He fell on his backside in the middle of the living room.

2.
adjective

located at the back (spatial, e.g. anatomical or physical position)

later in time; subsequent

Cette version est postérieure à la première édition.

This version is subsequent to the first edition.