compatibility vs variance

compatibility

noun
  • The state of being compatible; in which two or more things are able to exist or work together in combination without problems or conflict. 

  • the capability of two or more items or components of equipment or material to exist or function in the same system or environment without mutual interference. 

  • the capability that allows the substitution of one subsystem (storage facility), or of one functional unit (e.g., hardware, software), for the originally designated system or functional unit in a relatively transparent manner, without loss of information and without the introduction of errors. 

  • the continuity or good fit of material or members or components while being deformed. 

  • the ability to execute a given program on different types of computers without modification of the program or the computers. See backward compatibility and forward compatibility. 

variance

noun
  • A discrepancy between two legal documents. 

  • A departure from a cause of action originally in a complaint. 

  • An official permit to do something that is ordinarily forbidden by regulations. 

  • The act of varying or the state of being variable. 

  • The state of differing or being in conflict. 

  • The number of degrees of freedom in a system. 

  • Covariance and contravariance generally. 

  • A difference between what is expected and what is observed; deviation. 

  • The second central moment in probability. 

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