servitude vs slavery

servitude

noun
  • The state of being a slave; slavery; being forced to work for others or do their bidding without one's consent or against one's will, either in perpetuity or for a period of time over which one has little or no control. 

  • A qualified beneficial interest severed or fragmented from the ownership of an inferior property and attached to a superior property or to some person other than the owner; the most common form is an easement. 

slavery

noun
  • A condition of servitude endured by a slave. 

  • A condition in which one is captivated or subjugated, as by greed or drugs. 

  • An institution or social practice of owning human beings as property, especially for use as forced laborers. 

  • Forced labor in general, regardless of legality. 

adj
  • Covered in slaver; slobbery. 

How often have the words servitude and slavery occurred in a corpus of books? (source: Google Ngram Viewer )