physician
(6) Definitions In this subsection: (A) Medicare beneficiary The term “medicare beneficiary” means an individual who is entitled to benefits under part A or enrolled under part B. (B) Physician The term “physician” has the meaning given such term by paragraphs (1), (2), (3), and (4) of section 1395x(r) of this title . (C) Practitioner The term “practitioner” has the meaning given such term by section 1395u(b)(18)(C) of this title . (D) Opt-out physician or practitioner The term “opt-out physician or practitioner” means a physician or practitioner who has in effect an affidavit under paragraph (3)(B).