1. public address system an electronic amplification system used as a communication system in public areas
  2. electoral system a legal system for making democratic choices
  3. public transit a public transportation system for moving passengers
  4. ABO blood group system a classification system for the antigens of human blood
  5. lubricating system mechanical system of lubricating internal combustion engines in which a pump forces oil into the engine bearings
  6. public trust a trust created for charitable or religious or educational or scientific purposes
  7. Purkinje's system a network of Purkinje fibers that carry the cardiac impulse from the atrioventricular node to the ventricles of the heart and causes them to contract
  8. public discussion free and open discussion of some question of public interest
  9. guidance system a system of equipment for automatically guiding the path of a vehicle (especially a missile)
  10. public treasury a treasury for government funds
  11. political system the members of a social organization who are in power
  12. circulatory system the organs and tissues involved in circulating blood and lymph through the body
  13. public prosecutor a government official who conducts criminal prosecutions on behalf of the state
  14. public transport conveyance for passengers or mail or freight
  15. spoils system the system of employing and promoting civil servants who are friends and supporters of the group in power
  16. electrical system utility that provides electricity
  17. respiratory system the system for taking in oxygen and giving off carbon dioxide; in terrestrial animals this is accomplished by breathing
  18. speaker system electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance
  19. binary system a positional system of numeration that uses binary digits and a radix of two
  20. missile defense system naval weaponry providing a defense system