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simmer down

British  

verb

  1. informal (intr) to grow calmer or quieter, as after intense rage or excitement

  2. (tr) to reduce the volume of (a liquid) by boiling slowly

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
simmer down Idioms  

  1. Become calm after anger or excitement, as in Simmer down, Mary; I'm sure he'll make it up to you, or I haven't time to look at your report now, but I will when things have simmered down a bit. This idiom derives from simmer in the sense of “cook at low heat, below the boiling point.” [Second half of 1800s]

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.