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molecular weight

noun Chemistry.

the average weight of a molecule of an element or compound measured in units once based on the weight of one hydrogen atom taken as the standard or on 1/16 (0.0625) the weight of an oxygen atom, but after 1961 based on 1/12 (0.083) the weight of the carbon-12 atom; the sum of the atomic weights of all the atoms in a molecule. Abbreviation: mol. wt.

Origin of molecular weight

First recorded in 1875–80
Also called formula weight.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for molecular weight

molecular weight

noun

the former name for relative molecular mass
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
molecular weight in Medicine

molecular weight

n.

The sum of the atomic weights of all the atoms in a molecule.formula weight
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
molecular weight in Science

molecular weight

The sum of the atomic weights of the atoms contained in a molecule. Also called relative molecular mass
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
molecular weight in Culture

molecular weight

[(muh-lek-yuh-luhr)]

The sum of the atomic weights of all the atoms in a molecule.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.