casing vs cowling

casing

noun
  • The decorative trim around a door or window. 

  • That which encloses or encases. 

  • A metal pipe used to line the borehole of a well. 

  • The state of letter case across a whole phrase or whole lines of text; the collective state/arrangement of uppercase and lowercase letters. 

cowling

noun
  • A removable protective covering for the engine of an aircraft, motorcycle, etc. 

  • A young or little cow; calf. 

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