A suburb in Southern Sydney, also known as apart of the Sutherland Shire. Cronulla is famous for its' clean beaches, and infamous for the riots during 2005.
"Let's go down for a surf at 'nulla!"
"I'm going down to Cronulla for a surf!"
Not simply used to refer to a frequently used word as per the use in "a perfectly cromulent word" but may be better defined as germane, or apt, synonomous with appropriate, or fitting.
This defintion suits both uses in The Simpsons' famous episode.
Reporter - "And another racially charged riot occured in Cronulla today, apparently after some guy said he wanted a salad. That man had this to say..."
Man - "Give me salad!"