urology
Medical specialty dealing with the urinary tract and male reproductive organs.
He is majoring in urology.
泌尿器科 is the clinical department of urology, while 泌尿器科学 refers to the academic discipline or science of urology.
Compound of 泌尿器 (ひにょうき, 'urinary organs') + 科学 (かがく, 'science').