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molecular weight
noun
: 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
Its ultra-fine mist is infused with niacinamide for a shine-free finish and sodium hyaluronate—a derivative of hyaluronic acid that's smaller in molecular weight—to penetrate the surface layer of the skin for a hydrated, dewy finish.
—Jennifer Hussein, Allure, 3 Oct. 2024
Other larger peptides are able to repair damage at the surface of the cuticle, but a smaller molecular weight allows our peptides to penetrate all the way into the medulla, or the deepest parts of the hair’s core.
—Celia Shatzman, Forbes, 1 Oct. 2024
Small molecule drugs are made of chemicals that have low molecular weight, while biologic medicines are derived from living sources such as animals or humans.
—Annika Kim Constantino, CNBC, 15 Aug. 2024
Each has a different molecular weight, so the product can instantly revive dry, parched skin and provide additional moisture throughout the day (or night).
—Devon Abelman, Allure, 12 Aug. 2024
See all Example Sentences for molecular weight
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
Dictionary Entries Near molecular weight
Cite this Entry
“Molecular weight.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecular%20weight. Accessed 5 Nov. 2024.
Kids Definition
molecular weight
noun
: the weight of a molecule equal to the sum of the weights of the atoms contained in it
Medical Definition
molecular weight
noun
: 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
Britannica.com: Encyclopedia article about molecular weight
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