DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   simmer down
       v 1: become quiet or calm, especially after a state of
            agitation; "After the fight both men need to cool off.";
            "It took a while after the baby was born for things to
            settle down again." [syn: calm, calm down, cool off,
            chill out, simmer down, settle down, cool it]