1. either of the two rounded parts of the human body that form the bottom

Examples

• She fell and bruised her left buttock.
• The injection is given in the buttock muscle.
• He sat down hard and felt pain in his buttocks.
• The doctor examined the patient’s buttock for signs of injury.
• She rubbed her sore buttock after the long bike ride.
• The nurse administered the vaccine in the upper buttock area.