roentgen ray

noun

often capitalized 1st R

: x-ray

Word History

First Known Use

circa 1890, in the meaning defined above

Time Traveler

The first known use of roentgen ray was circa 1890

See more words from the same year

Cite this Entry

Style

“Roentgen ray.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/roentgen%20ray. Accessed 25 May. 2025.

Copy Citation

Kids Definition

roentgen ray

noun

often capitalized 1st R

: x-ray

Medical Definition

roentgen ray

noun

: x-ray sense 1

More from Merriam-Webster

Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.

Can you solve 4 words at once?

Can you solve 4 words at once?

Word of the Day

dyspeptic

Listen to the pronunciation of dyspeptic

See Definitions and Examples »

Get Word of the Day daily email!

Popular in Grammar & Usage

'Affect' vs. 'Effect'

Using Bullet Points ( • )

Homophones, Homographs, and Homonyms

Words You Always Have to Look Up

Democracy or Republic: What's the difference?

Popular in Wordplay

Top 12 Sophisticated Compliments

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

8 Words for Lesser-Known Musical Instruments

Birds Say the Darndest Things

10 Words from Taylor Swift Songs (Merriam's Version)

Popular

'Affect' vs. 'Effect'

Top 12 Sophisticated Compliments

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