contact lens vs linkage

contact lens

noun
  • A thin lens, made of flexible or rigid plastic, that is placed directly on to the eye to correct vision, used as an alternative to spectacles, or, if coloured, to change one's eye color cosmetically. 

linkage

noun
  • A mechanical device that connects things. 

  • A connection or relation between things or ideas. 

  • The act or result of linking: the combination of multiple object files into one executable, library, or object file. 

  • A United States foreign policy, during the 1970s détente in the Cold War, of persuading the Soviet Union to co-operate in restraining revolutions in the Third World in return for nuclear and economic concessions. 

  • The property of genes of being inherited together. 

  • A set of definitely related languages for which no proto-language can be derived, typically a group of languages within a family that have formed a sprachbund. 

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