The Collaborative International Dictionary of English v.0.48:

azidothymidine \azidothymidine\ n.
   1. 1 an antiviral drug, (C10H13N5O4) used in the treatment
      of AIDS. It has the generic name of zidovudine.

   Note: an analog of thymidine, it inhibits the replication of
         the viral chromosome.

   Syn: AZT, zidovudine[generic], 3'-azido 3'-deoxythymidine,
        Retrovir[Trademark]
        [WordNet 1.5 +PJC]