underline

The term "underline" means to mark something with a line underneath it, often to indicate its importance or to emphasize it. It can also refer to stressing or highlighting a particular point in a discussion or text. In printing, it is used to indicate emphasis, similar to italicizing.
Merriam Webster
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Merriam Webster
UNDERLINE Definition & Meaning - Merriam-Webster

The Free Dictionary
Underline - definition of underline by The Free Dictionary



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Merriam Webster
UNDERLINE Definition & Meaning - Merriam-Webster
Learn the meaning of underline as a verb and a noun, with synonyms, examples, and word history. See also related words, rhymes, and translations of underline.
https://www.merriam-webster.com

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unterstreichen
Similar and Opposite Words
verb
draw a line under (a word or phrase) to give emphasis or indicate special type:
underscore
mark
pick out
emphasize
highlight
italicize
emphasize (something):
emphasize
stress
highlight
accentuate
accent
spotlight
foreground
point up

Opposite:
play down
minimize

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underline
1 of 2
verb
un·;der·;line ;;n-d;r-;l;n  ;;n-d;r-;l;n
underlined; underlining; underlines
Synonyms of underline
transitive verb

1
: to mark (something, such as a word) with a line underneath
2
: to put emphasis on : stress
3
: to show clearly or emphatically
underline

2 of 2
noun
un·;der·;line ;;n-d;r-;l;n
1
: the outline of a quadruped's underbody
also : the ventral surface of a quadruped's body
2
: a horizontal line placed underneath something

Synonyms
Verb

emphasize
reinforce
Examples of underline in a Sentence
Verb
His name was underlined in the book.
The accident underlines our need for better safety procedures.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Verb
Fritz continued serving well in the third set, but was quickly broken to love, underlining why playing Alcaraz is arguably the toughest challenge in the sport.
—Charlie Eccleshare, New York Times, 11 July 2025
Prices for secondhand apartments have fallen, too, deepening Beijing’s property woes and underlining China’s challenges beyond the US trade war, CNBC wrote.
—semafor.com, 10 July 2025
Noun
The data and lessons emerging today underline why this shift has become so critical, not just for families but for the future workforce.
—Glenn Llopis, Forbes.com, 28 June 2025
That the ambition existed at all underlines how the two most powerful bodies in world football are in a forever war for the economic and political control of the global game.
—Adam Crafton, New York Times, 21 May 2025

Word History
First Known Use
Verb

1721, in the meaning defined at sense 1

Noun

1886, in the meaning defined at sense 1

Time Traveler
The first known use of underline was in 1721
See more words from the same year