A.Word.A.Day on Twitter: "Today's term is the CAT'S PAJAMAS. In the 1920s, it was fashionable to coin terms on the pattern of "animal's something". Some synonyms of today's term are bee's knees,
2 A.M. at The Cat's Pajamas by Marie-Helene Bertino | Goodreads
The saying 'The cat's pajamas' - meaning and origin.