cohabitation vs relationship

cohabitation

noun
  • The act of living together. 

  • A place where two or more individuals reside together. 

  • The act of two species living together in the same habitat. 

  • An emotional and physical intimate relationship which includes a common living place and which exists without legal or religious sanction. 

  • Cooperation between politicians of opposing political parties; especially, in France, between a President and Prime Minister. 

relationship

noun
  • A way in which two or more people behave and are involved with each other 

  • The level or degree of affinity between keys, chords and tones. 

  • The links between the x-values and y-values of ordered pairs of numbers especially coordinates. 

  • Connection or association; the condition of being related. 

  • Kinship; being related by blood or marriage. 

  • A romantic or sexual involvement. 

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