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 It’s formulated with hydrolyzed proteins, which are composed of low molecular weight peptides that can be absorbed in the digestive tract to reduce risk of triggering an immune reaction. Amber Smith, Discover Magazine, 17 Oct. 2022 Delta 8 has a molecular weight of 314.47 g/mol and a boiling point of 175-178°C (347-352°F). Amber Smith, Discover Magazine, 3 Sep. 2023 The condition is typically treated with aspirin and low molecular weight heparin (LMWH) during pregnancy. Sadia Rafiquddin, STAT, 31 Aug. 2023 With that in mind, a formula with two different molecular weights of hyaluronic acid can penetrate more optimally and promote longer-lasting hydration. Jessie Quinn, Peoplemag, 4 Aug. 2023 Molecular Weight For a more potent hyaluronic acid serum, Dr. Engelman recommends considering molecular weight. Jessie Quinn, Peoplemag, 4 Aug. 2023 The point of this was twofold: the smaller molecular weight allows the product to penetrate deeper into the hair strand. Megan Decker,, 31 May 2023 Their results showed that, for relatively small molecules, the assembly index is roughly proportional to molecular weight. Philip Ball, Quanta Magazine, 4 May 2023 Each capsule has 120 mg of this low molecular weight hyaluronic acid which is the type and amount shown in studies to provide skin health benefits.12 Ceratiq: Probably not as popular as hyaluronic acid for skin health, this ingredient comes from wheat oil extract. Holly Klamer, Ms, Verywell Health, 4 May 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'molecular weight.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1860, in the meaning defined above

Time Traveler
The first known use of molecular weight was in 1860

Dictionary Entries Near molecular weight

Cite this Entry

“Molecular weight.” Dictionary, Merriam-Webster, Accessed 8 Dec. 2023.

Kids Definition

molecular weight

: the weight of a molecule equal to the sum of the weights of the atoms contained in it

Medical Definition

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

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