OPD is Outpatient departments. These are basically clinics. You go there, get an appointment or request to see a doctor, usually of a certain specialty like gynecology or pediatrics etc.
Emergency Departments are different. These are where you go when there is an emergency like you get into a bad accident, or you suddenly develop a severe headache or you started to bleed from your nose for no reason, or whatever else you feel is something you cannot sleep on. The doctors in this part of the hospital do acute management of patient’s problems. These are not doctors who can advise you on whether you need a certain chemotherapy treatment for your cancer or who do procedures like Colonoscopy to figure out if you have colon cancer and then manage it. No, these docs deal with acute issues and if the issue is one that requires you to be seen by a specialist in a different field (such as Gastroenterologist or a Surgeon in the case of Colonoscopy for Colon cancer), these doctor will refer you to the OPD clinics or to a specialized center where you can follow with a specialized doctor for long-term care and management.

Others Department