What is the meaning of "ambulatory surgical center"?

Outpatient surgery, also known as ambulatory surgery, same-day surgery, day case, or day surgery, is surgery that does not require an overnight hospital stay. The term “outpatient” arises from the fact that surgery patients may go home and do not need an overnight hospital bed. Or this operative procedures performed on patients who are admitted to and discharged from a hospital on the same day. They basically say the same thing 

Modern health care facilities focused on providing same - day surgical care.