spec vs uncertainty

spec

verb
  • To specify, especially in a formal specification document. 

noun
  • A spectacular mark (catch) in Australian rules football. 

uncertainty

noun
  • Doubt; the condition of being uncertain or without conviction. 

  • A parameter that measures the dispersion of a range of measured values. 

  • Something uncertain or ambiguous. 

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