胳膊
gē bo · HSK 7
arm
💪 胳膊 = 胳 (armpit/upper arm) + 膊 (upper arm/shoulder); both flesh-radical 月 body parts
Both characters carry the 月 (flesh) radical, marking them as body parts. 胳 originally meant armpit, 膊 the upper arm — paired together they cover the whole arm. The reading gē bo is colloquial, with 膊 toned down to neutral.