1. rhesus factor a blood group antigen possessed by Rh-positive people
  2. Rh factor a blood group antigen possessed by Rh-positive people
  3. risky venture a wild and exciting undertaking (not necessarily lawful)
  4. think factory a company that does research for hire and issues reports on the implications
  5. risk taker someone who risks loss or injury in the hope of gain or excitement
  6. scale factor a number used as a multiplier in scaling
  7. releasing factor a substance produced by the hypothalamus that is capable of accelerating the secretion of a given hormone by the anterior pituitary gland
  8. causal factor a determining or causal element or factor
  9. prime factor the prime factors of a quantity are all of the prime quantities that will exactly divide the given quantity
  10. cofactor a substance (as a coenzyme) that must join with another to produce a given result
  11. radius vector a line connecting a point in space to the origin of a polar coordinate system
  12. benefactor a person who helps people or institutions
  13. intrinsic factor a substance produced by the mucosa of the stomach and intestines that is essential for the absorption of vitamin B12
  14. screen actor an actor who plays a role in a film
  15. refectory a communal dining-hall, usually in a monastery
  16. load factor the ratio of an external load to the weight of the aircraft
  17. justificatory attempting to justify or defend in speech or writing
  18. refuse collector someone employed to collect and dispose of refuse
  19. decisive factor a point or fact or remark that settles something conclusively
  20. factor anything that contributes causally to a result