Okay, all you word-puzzle-heads: here's a tough one. These twelve entries are given in a particular order. Identify the sequence (please answer via comment), and the first correct will win a mental_floss T-shirt of his or her choice!

  1. years
  2. uterus
  3. enigma
  4. accent
  5. owl
  6. ivory
  7. rabbi
  8. tropics
  9. magistratus
  10. scrap iron
  11. quasi-art
  12. biceps