1. protest march occasion when you can express opposition by marching (usually on some government institution) without a license
  2. pro tempore for the time being
  3. trade embargo a government order imposing a trade barrier
  4. British Empire a former empire consisting of Great Britain and all the territories under its control; reached its greatest extent at the end of World War I; it included the British Isles, British West Indies, Canada, British Guiana; British West Africa, British East Africa, India, Australia, New Zealand
  5. producer someone who manufactures something
  6. Persian Empire an empire in southern Asia created by Cyrus the Great in the 6th century BC and destroyed by Alexander the Great in the 4th century BC
  7. prodromic symptomatic of the onset of an attack or a disease
  8. product research marketing research that yields information about desired characteristics of the product or service
  9. prothrombin a protein in blood plasma that is the inactive precursor of thrombin
  10. protoceratops small horned dinosaur
  11. producer price index an index of changes in wholesale prices
  12. prodigious great in size, force, extent, or degree
  13. producer gas a gas made of carbon monoxide and hydrogen and nitrogen
  14. prodrome an early symptom that a disease is developing or that an attack is about to occur
  15. disembark exit from a ship, vehicle, or aircraft
  16. Bromberg an industrial city and river port in northern Poland
  17. Bertram Brockhouse Canadian physicist who bounced neutron beams off of atomic nuclei to study the structure of matter (1918-2003)
  18. preterm baby an infant that is born prior to 37 weeks of gestation
  19. predecessor one who goes before you in time
  20. prodigy an unusually gifted or intelligent person