overcoating vs topcoat

overcoating

noun

  • cloth for making overcoats 

topcoat

noun

  • A layer of paint or varnish etc. applied after the undercoat. 

  • A light overcoat. 

verb

  • To apply a topcoat to. 

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