ret·ro·vi·rus /ˈrɛtroˌvaɪrəs/
  反向病毒
  ret·ro·vi·rus /ˈrɛtroˌvaɪrəs/ 名詞
  逆轉錄病毒
  retrovirus
       n : any of a group of viruses that contain two single-strand
           linear RNA molecules per virion and reverse transcriptase
           (RNA to DNA)