in short vs lastly

in short

prep
  • As a summary; as a shortened version of what has been told or what would have been told. 

lastly

adv
  • Used to signal that the speaker is about to yield control of the conversation. 

  • Used to mark the beginning of the last in a list of items or propositions. 

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