der·ri·ere or der·ri·ère 
/ˌderiˈeɚ/ noun
plural der·ri·eres or der·ri·ères /ˌderiˈeɚ/ noun [count] humorous : the part of the body you sit on : buttocks
▪ I slipped on the ice and fell on my derriere.
▪ I slipped on the ice and fell on my derriere.
