Whit vs umbra

Whit

noun
  • The season of Whitsuntide. 

umbra

noun
  • The fully shaded inner region of a shadow cast by an opaque object. 

  • The area on the earth or moon experiencing the total phase of an eclipse. 

  • The central region of a sunspot. 

  • One of the family Umbridae of mudminnows. 

  • A shadow. 

  • A sciaenoid fish, the umbrine. 

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