massless

American  

[mas-lis] / ˈmæs lɪs /

adjective

Physics.

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

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Other Word Forms

• masslessness
  noun

Etymology

Origin of massless

First recorded in 1875–80; mass + -less

Example Sentences

But while his classification system is accurate for particles with mass, it produces inaccurate results for massless particles, like photons.

From Science Daily • May 23, 2024

Neutrinos, which are nearly massless and almost undetectable, come in three types and can morph from one to another as they zip along at light speed.

From Science Magazine • Dec. 8, 2023

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

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