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massless

American

[mas-lis] / ˈmæs lɪs /

adjective

Physics.

pertaining to an elementary particle having zero rest mass, as a photon.

Other Word Forms

masslessness noun

Etymology

Origin of massless

First recorded in 1875–80; mass + -less

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Neutrinos are extremely small, nearly massless particles that constantly pass through space, planets, and even our bodies, yet rarely interact with anything.

From Science Daily • Mar. 3, 2026

At first, they were predicted to be massless, but now scientists know they must have nonzero mass.

From Scientific American • Jun. 7, 2023

Posting publicly on Twitter, TikTok, YouTube, or Instagram is a lot like using a megaphone to scream to a large, massless, faceless crowd.

From Slate • Nov. 30, 2022

Yet the nearly massless particles interact with other matter so feebly that the experiment, known as T2K, has captured fewer than 600 of them.

From Science Magazine • Sep. 28, 2022

The electromagnetic attraction is pictured as being caused by the exchange of large numbers of virtual massless particles of spin 1, called photons.

From "A Brief History of Time: And Other Essays" by Stephen Hawking

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023