1. open door freedom of access
  2. operator an agent that operates some apparatus or machine
  3. opened not sealed or having been unsealed
  4. open air where the air is unconfined
  5. open-air in the open air
  6. spender someone who spends money to purchase goods or services
  7. indoor located, suited for, or taking place within a building
  8. open order a military formation leaving enough space between ranks to allow an inspecting officer to pass
  9. opener a hand tool used for opening sealed containers
  10. Spender English poet and critic (1909-1995)
  11. open letter a letter of protest
  12. up in the air not yet determined
  13. abandon forsake; leave behind
  14. open fire start firing a weapon
  15. upended turned up on end
  16. open-eyed carefully observant or attentive
  17. ependyma thin epithelial membrane lining the ventricles of the brain and the spinal cord canal
  18. Pandora the first woman
  19. epanodos repetition of a group of words in reverse order
  20. Oppenheimer United States physicist who directed the project at Los Alamos that developed the first atomic bomb (1904-1967)