Main vs Tone

Main

name
  • A river in Northern Ireland, flowing into Lough Neagh. 

  • A river in southern Germany, flowing from Bavaria to the Rhine. 

  • A surname. 

Tone

name
  • A river in Somerset, England, which flows into the River Parrett. 

  • A male given name, a short form of Anthony/Antony 

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