cheek

SMART Vocabulary: related words and phrases

The buttocks
arse
ass
back end
backside
behind
booty
bot
bottom
bum
bun
duff
fundament
gluteal
gluteus maximus
haunch
posterior
rear
rump
seat
tush

Examples from literature

A man who was shot through the buttocks, or wounded in the back, was laughed at and disgraced. 
His body is excessively smooth and white, the hips and buttocks rounded. 
Needling or acupuncture consists in piercing the nerve at intervals in the buttock and thigh with long steel needles. 
The patient complains of persistent aching and stiffness over the buttock, and sometimes extending down the lateral aspect of the thigh. 

buttock | American Dictionary

buttock
noun[ Cusually pl ]
us/ˈbʌt̬·ək/
either of the two soft parts of the body below the back that support the body when sitting