intransitive verb
Etymology: simmer (I)
1. : to become reduced by or as if by simmering
let the broth simmer down to a rich stock
it … all simmers down to a matter of design — E.B.White
2. : to become calm or peaceful : quiet , relax
protests angrily but soon simmers down
time would have elapsed for things to simmer down — Nevil Shute
early May days find social activities simmering down a bit — Alice Dameron