1. abstruse difficult to understand
  2. anestrous (of lower mammals) not in a state of estrus; not in heat
  3. ancestress a woman ancestor
  4. disastrous having extremely unfortunate or dire consequences
  5. ice storm a storm with freezing rain that leaves everything glazed with ice
  6. associatory characterized by or causing or resulting from the process of bringing ideas or events together in memory or imagination
  7. anoestrous of or relating to anestrus
  8. estrous (of lower mammals) showing or in a state of estrus; in heat
  9. anoestrus applies to nonhuman mammals: a state or interval of sexual inactivity between two periods of estrus
  10. Osteostraci extinct group of armored fish-like vertebrates
  11. assistance the activity of contributing to the fulfillment of a need
  12. easy street financial security
  13. osseous tissue the porous calcified substance from which bones are made
  14. necessitous poor enough to need help from others
  15. ancestral of or inherited from someone from whom you are descended
  16. genus Oestrus type genus of the Oestridae: sheep botflies
  17. genus Citrus orange; lemon; lime; etc.
  18. Associate in Arts an associate degree in arts
  19. ancestor someone from whom you are descended
  20. Austrocedrus one species; formerly included in genus Libocedrus