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 What separates these drops from the crowd is the inclusion of niacinamide and dual molecular weight hyaluronic acid, which pull their weight to even the skin tone, smooth over fine lines, and give the skin a more youthful glow. Alyssa Brascia, Peoplemag, 30 Jan. 2024 Two molecular weights of hyaluronic acid lead the formula to replenish the skin's moisture levels and reveal a bouncier complexion. Lauren Valenti, Vogue, 12 Jan. 2024 Most new antibiotics are small molecules—those that have molecular weights of less than 600 daltons. Beth Mole, Ars Technica, 5 Jan. 2024 Cassini’s samples, analyzed by the spacecraft’s onboard mass spectrometer (an instrument that identifies compounds by their molecular weight), had initially revealed five types of molecules in the jets: water, carbon dioxide, methane, ammonia and molecular hydrogen. Ling Xin, Scientific American, 14 Dec. 2023 But hydrogen is a wily gas, with a molecular weight as light as molecules come. IEEE Spectrum, 31 July 2014 Hydrolyzed soy protein is made of low molecular weight peptides, which are highly digestible. Amber Smith, Discover Magazine, 23 Oct. 2022 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

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.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/molecular%20weight. Accessed 29 Mar. 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

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