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inch of mercury

American  

noun

  1. a unit of atmospheric pressure, being the pressure equal to that exerted by a column of mercury one inch high under standard conditions of temperature and gravity: 33.864 millibars. in. Hg

Etymology

Origin of inch of mercury

First recorded in 1825–35

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.