fixity vs single-mindedness

fixity

noun
  • The state or condition of being fixed. 

  • The position of an operator relative to its operand (prefix, postfix) or operands (infix). 

  • Something fixed. 

single-mindedness

noun
  • The property of being single-minded. 

How often have the words fixity and single-mindedness occurred in a corpus of books? (source: Google Ngram Viewer )