gynecology department
Refers to the hospital department or clinic section specializing in women's health.
The gynecology department is on the third floor.
gynecology
Refers to the medical specialty itself, not the physical department.
She specializes in gynecology.
My periods had been irregular, so I went to the gynecology department.
I make a point of having a gynecology checkup once a year.
産婦人科 covers both obstetrics and gynecology, whereas 婦人科 refers only to the gynecology side of women's health.
婦人科 covers gynecology and the female reproductive system generally, while 産科 focuses specifically on pregnancy and childbirth.
Compound of 婦人 (woman) and 科 (department, field of study).