short form vs shortening

short form

noun
  • A word with the same meaning as another formed by removing one or more of the syllables of the longer word, and considered a word in its own right rather than an abbreviation. 

  • Particularly in Slavic languages, a shortened form of the adjective, used predicatively. 

shortening

noun
  • Fat that is solid at room temperature, such as margarine or lard (not usually used of butter), used to make shortcrust pastry. 

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