1. production line mechanical system in a factory whereby an article is conveyed through sites at which successive operations are performed on it
  2. product line a particular kind of product or merchandise
  3. prodigious great in size, force, extent, or degree
  4. credit line the maximum credit that a customer is allowed
  5. protriptyline tricyclic antidepressant used to treat clinical depression
  6. prisonlike resembling a prison
  7. predetermine establish beforehand
  8. regression line a smooth curve fitted to the set of paired data in regression analysis; for linear regression the curve is a straight line
  9. superstitious notion an irrational belief arising from ignorance or fear
  10. protozoan of or relating to the Protozoa
  11. predetermination a mental determination or resolve in advance
  12. party line the policy of a political group
  13. predatory animal any animal that lives by preying on other animals
  14. protozoon any of diverse minute acellular or unicellular organisms usually nonphotosynthetic
  15. Proteus anguinus European aquatic salamander with permanent external gills that lives in caves
  16. partisan a fervent and even militant proponent of something
  17. parotid gland a large salivary gland that produces 50% of daytime saliva
  18. borderline a line that indicates a boundary
  19. Robert Anson Heinlein United States writer of science fiction (1907-1988)
  20. prototherian primitive oviparous mammals found only in Australia and Tasmania and New Guinea