phosphor

noun

phos·​phor ˈfäs-fər How to pronounce phosphor (audio)
-ˌfȯr
variants or less commonly phosphore
ˈfäs-ˌfȯr How to pronounce phosphor (audio)
-fər
1
: a phosphorescent substance
2
: a luminescent substance that emits light when excited by radiation (such as electrons) and is used especially in fluorescent lamps and cathode-ray tubes

Examples of phosphor 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.
Paired with that is a laser-phosphor light source that produces four primary colors, using a blue laser and a color wheel. — M. David Stone, PC Magazine, 18 Oct. 2026 Companies processed heavy mineral sands from Australia, Brazil, and India, and hard rock from South Africa, to produce rare earths for tracer ammunition, steel alloys, cigarette-lighter flints, and, later, color-TV phosphors. — Glenn Zorpette, IEEE Spectrum, 15 Oct. 2026 Scientists began describing minerals that glowed in the dark as phosphors in the Middle Ages. — ArsTechnica, 25 Aug. 2026 The element plays an important role in superconductors, advanced alloys, ceramics, phosphors, and other high-performance technologies. — Aamir Khollam, Interesting Engineering, 24 July 2026 See All Example Sentences for phosphor

Word History

Etymology

Latin phosphorus, from Greek phōsphoros, literally, light bringer, from phōsphoros light-bearing, from phōs light + pherein to carry, bring — more at fancy, bear

First Known Use

1706, in the meaning defined at sense 1

Time Traveler
The first known use of phosphor was in 1706

Phrases Containing phosphor

Rhymes for phosphor

See All Rhymes for phosphor

Browse Nearby Words

phosphoprotein
phosphor
phosphoramidic acid
See all Nearby Words

Cite this Entry

“Phosphor.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/phosphor. Accessed 27 Oct. 2026.

Copy Citation

Kids Definition

phosphor

noun
phos·​phor ˈfäs-fər How to pronounce phosphor (audio)
-ˌfȯ(ə)r
: a substance exhibiting phosphorescence

Medical Definition

phosphor

noun
phos·​phor ˈfäs-fər, -ˌfȯ(ə)r How to pronounce phosphor (audio)
variants also phosphore
-ˌfō(ə)r, -ˌfȯ(ə)r, -fər How to pronounce phosphor (audio)
: a phosphorescent substance
specifically : a substance that emits light when excited by radiation

More from Merriam-Webster on phosphor

Britannica.com: Encyclopedia article about phosphor

Love words? Need even more definitions?

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

Last Updated: - Updated example sentences

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of milieu

See Definitions and Examples »

Popular in Grammar & Usage

See More

How to Use 'Who' vs. 'Whom'

Merriam-Webster’s Great Big List of Words You Love to Hate

'Affect' vs. 'Effect'

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

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

Popular in Wordplay

See More

The Longest Long Words List

9 Words That Sound Like Insults But Aren't

12 Lovely and Unusual Words for the Natural World

Why do we 'bury the lede?'

'Za' and 9 Other Words to Help You Win at SCRABBLE
See More

Popular

See More

How to Use 'Who' vs. 'Whom'

The Longest Long Words List

9 Words That Sound Like Insults But Aren't
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
different halloween monsters in silhouette
A Monstrous Vocab Quiz Words That Go Bump in the Night
See All