plimsoll vs thong

plimsoll

noun
  • A rubber-soled lace-up canvas shoe for sports or onboard ships; a precursor of trainers. 

  • The plimsoll symbol ⦵ (or o) that is used as a superscript in the notation of thermodynamics to indicate an arbitrarily chosen non-zero reference point. 

thong

noun
  • An item of footwear, usually of rubber, secured by two straps which join to pass between the big toe and its neighbour. 

  • The largest section of a bullwhip constructed of many straps of braided leather. 

  • A strip of leather. 

  • An undergarment or swimwear consisting of very narrow strips designed to cover just the genitals and nothing more. 

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