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 While low- and medium-molecular-weight HAs do the classic hyaluronic acid job of attracting and binding water, higher molecular weight HA tends to have a more occlusive effect, sealing in that hydration. Sarah Jacoby, SELF, "Hyaluronic Acid Benefits: This Ingredient Is a Skin-Care Superstar for Good Reason," 3 Oct. 2019 In practice, though, Dr. Newsom says that molecular weight isn’t really something to spend your time worrying about. Sarah Jacoby, SELF, "Hyaluronic Acid Benefits: This Ingredient Is a Skin-Care Superstar for Good Reason," 3 Oct. 2019 The new armor technology takes ultrahigh molecular weight polyethylene, or UHMWPE, and adds silica nanoparticles for strength. Kyle Mizokami, Popular Mechanics, "The Army Could Field Armor Based on Pearls and LEGOs," 24 Sep. 2019 In addition to the molecular shrinkage that happens during the freeze-drying process, each tablet is formulated with hyaluronic acid of the lowest molecular weight to begin with. Rebecca Dancer, Allure, "Facialist Georgia Louise Launches the Pure Molecule, Freeze-Dried Skin-Care Tablets," 18 Apr. 2019 Their results showed that the brown algae extract, which had the lowest molecular weight, did the best. Sarah Jacoby, SELF, "Can Spirulina and Other Algae Skin-Care Products Live Up to the Hype?," 13 Aug. 2019 That’s a more buoyant air mass, and that’s due to the molecular weight of a wet air mass versus a dry one. Chris Bianchi, The Denver Post, "When you see this number, it probably means storms are on the way," 3 Aug. 2019 This movement toward subtlety picked up steam in 2016 with the FDA approval of Juvéderm Volbella XC, which combines multiple molecular weights of hyaluronic acid for a softer fill. Brennan Kilbane, Allure, "Dermatologists Are Now Using Fillers to Simulate Instagram Filters, So I Decided to Try It," 19 Apr. 2018 Once the pulmonary embolism is diagnosed, treatment with intravenous heparin, or injections of low-molecular weight heparin, both blood thinners, is started to treat the clot. Sandy Bauers,, "5 Questions: Lessons from the early death of Maroon 5 manager Jordan Feldstein," 6 Apr. 2018

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.

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First Known Use of molecular weight

1860, in the meaning defined above

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The first known use of molecular weight was in 1860

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Cite this Entry

“Molecular weight.” Dictionary, Merriam-Webster, Accessed 7 Jul. 2020.

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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

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