noun
Anatomical term for the organ that stores urine. In everyday conversation, 膀胱 is the standard word.
膀胱に尿がたまると、トイレに行きたくなる。
When urine accumulates in the bladder, you feel the urge to go to the bathroom.
膀胱炎は女性に多い病気
Cystitis is a common condition among women.
The kanji 膀 (side of the body) and 胱 (bladder) combine to specifically denote the urinary bladder. The reading ぼうこう is the on'yomi of these characters.