massless

adjective

mass·​less ˈmas-ləs How to pronounce massless (audio)
: having no mass
a massless particle

Examples of massless in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Relativity does indeed state that an object with non-zero mass cannot go at the speed of light, and even massless objects cannot go faster than light. — Don Lincoln, Big Think, 29 Aug. 2025 If a certain symmetry in the models was broken, the massless partner would go away, leaving only a massive one. — Jennifer Ouellette, Ars Technica, 9 Sep. 2022 Neutrinos are virtually massless particles that stream through the cosmos at nearly the speed of light. — Robert Lea, Space.com, 9 Jan. 2026 Neutrinos are nearly massless particles produced in the sun and in energetic events like supernovas, colliding stars, and gamma-ray bursts. — Korey Haynes, Discover Magazine, 23 May 2019 See All Example Sentences for massless

Word History

First Known Use

1879, in the meaning defined above

Time Traveler
The first known use of massless was in 1879

Rhymes for massless

See All Rhymes for massless

Browse Nearby Words

Mass John
massless
mass-luminosity law
See all Nearby Words

Cite this Entry

“Massless.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/massless. Accessed 10 Jul. 2026.

Copy Citation
Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

Is that lie 'bald-faced' or 'bold-faced'?

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)
See More

Popular in Wordplay

See More

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List

One-Word Oxymorons: Bittersweet, Spendthrift, and More

Ten Words Ending with a Silent ‘T’

The Words of the Week - Jul 10
See More

Popular

See More

Is that lie 'bald-faced' or 'bold-faced'?

14 Phobias You Probably Haven't Heard Of

The Longest Long Words List
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
banana-mirrored
Contradictory Words Quiz Pick out which word means one thing…and the opp...
See All