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

Boasting three unique molecular weights of hyaluronic acid (HA), this serum includes macro HA for intensive hydration, micro HA for smooth skin texture, and micro-epidermic HA for fast product absorption. —Conçetta Ciarlo, Vogue, 2 Dec. 2024

Molecular Weight For a more potent hyaluronic acid serum, Dr. Engelman recommends considering molecular weight. —Jessie Quinn, People.com, 1 Nov. 2024

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, People.com, 1 Nov. 2024

There are four different molecular weights of hyaluronic acid in this formula, meaning the ingredient can penetrate the skin to different depths and create a volumizing effect at multiple levels of the skin. —Emily Orofino, Allure, 29 Oct. 2024

Word History

First Known Use

1860, in the meaning defined above

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