EDGE vs plus sign

EDGE

noun
  • Notation for an edge rusher. 

  • Explain, demonstrate, guide, enable; an educating method. 

plus sign

noun
  • The symbol + used to denote the operation of addition, to indicate that a number is positive, and so on. 

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