molecular weight


Definition of molecular weight

: the average mass of a molecule of a compound compared to ¹/₁₂ the mass of carbon 12 and calculated as the sum of the atomic weights of the constituent atoms

Examples of molecular weight in a Sentence

Recent Examples on the Web Aside from being highly durable thanks to a polyethylene with ultra high molecular weight, the fabric is DWR-treated and completely waterproof. Outside Online, 23 June 2022 The Hyaluronic Acid Serum is $90, and a multi-molecular weight hyaluronic acid serum that provides 72-hours of moisturizer, reducing dehydration and fine lines. Allyson Portee, Forbes, 1 July 2022 This ultra hydrating serum is formulated with mixed molecular weight hyaluronic acid and niacinamide to plump and rejuvenate the skin, reduce fine lines, increase skin firmness, and improve elastin production. Cécilia Pelloux, Forbes, 2 June 2022 From there, the researchers took tiny quantities of each beer and used two mass spectrometers (a tool that helps scientists measure a sample's exact molecular weight) to perform a chemical analysis in two different ways. Caroline Delbert, Popular Mechanics, 27 Aug. 2021 So, all small molecules have low molecular weight, but not all small molecules are drugs by any means. Caroline Delbert, Popular Mechanics, 6 July 2021 Honorable mention in the senior division was won by John Bernardin of Fallbrook Union High School for a colorimetric chemical analysis exhibit, and Lulu Capra of Fallbrook for a display showing how to measure molecular weight. Merrie Monteagudo, San Diego Union-Tribune, 16 Apr. 2021 The team could measure this aboard the aircraft with a device called a mass spectrometer, which calculates molecular weight. Matt Simon, Wired, 3 Nov. 2020 But Fuster said low molecular weight heparin and apixaban both showed positive effects. Maggie Fox, CNN, 26 Aug. 2020 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'molecular weight.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of molecular weight

1860, in the meaning defined above

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Time Traveler for molecular weight

Time Traveler

The first known use of molecular weight was in 1860

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Dictionary Entries Near molecular weight

molecular volume

molecular weight


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Statistics for molecular weight

Last Updated

6 Aug 2022

Cite this Entry

“Molecular weight.” Dictionary, Merriam-Webster, Accessed 9 Aug. 2022.

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More Definitions for molecular weight

molecular weight


Medical Definition of molecular weight

: the mass of a molecule that may be calculated as the sum of the atomic weights of its constituent atoms

More from Merriam-Webster on molecular weight Encyclopedia article about molecular weight


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