nurse practitioner

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A registered nurse with special training for providing primary health care, including many tasks customarily performed by a physician.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun medicine A professional medical designation recognized in some jurisdictions, denoting an individual who is fully qualified as a nurse and who has additional qualifications and authorization to provide some diagnoses and/or treatments which can otherwise be provided only by a licensed medical doctor.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a registered nurse who has received special training and can perform many of the duties of a physician