noun, often attributive
break·​through | \ ˈbrāk-ˌthrü How to pronounce breakthrough (audio) \

Definition of breakthrough

 (Entry 1 of 2)

1 warfare : an offensive military assault that penetrates and carries beyond a defensive line
2 : an act or instance of moving through or beyond an obstacle a breakthrough in the talks between the region's leaders a breakthrough agreement
3a : a sudden advance especially in knowledge or technique a medical breakthrough
b : a person's first notable success a breakthrough novel the actress's breakthrough performance

break through

broke through; broken through; breaking through; breaks through

Definition of break through (Entry 2 of 2)

intransitive verb

: to make a breakthrough

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Synonyms & Antonyms for breakthrough

Synonyms: Noun

Antonyms: Noun

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Examples of breakthrough in a Sentence

Noun Researchers say they have made a major breakthrough in cancer treatment. The police have announced a breakthrough in the murder case. This job could be the breakthrough she's been waiting for.
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Recent Examples on the Web: Noun The experience, Harvey believes, has set MSR up for a breakthrough at some point, after six top-10 finishes a year ago with a best-finish of 6th in Race 2 at the Harvest Grand Prix. Nathan Brown, The Indianapolis Star, "Colton Herta rebounds from early Barber crash to take pole for Sunday at St. Pete," 24 Apr. 2021 Could new variants be causing 'breakthrough' cases? Erin Schumaker, ABC News, "What to know about expected but rare 'breakthrough' COVID cases," 9 Apr. 2021 Otherwise, Iran has vowed to erase the recordings, narrowing the window for a diplomatic breakthrough. David Rising, Star Tribune, "Positive atmosphere, little progress in Iran nuclear talks," 9 Apr. 2021 Otherwise, Iran has vowed to erase the recordings, narrowing the window for a diplomatic breakthrough. Time, "World Powers Are Seeking to Bring the U.S. Back Into the Iran Nuclear Deal," 7 Apr. 2021 Otherwise, Iran has vowed to erase the recordings, narrowing the window for a diplomatic breakthrough. Tracy Wilkinson Staff Writer, Los Angeles Times, "World powers seek to bring U.S. back into Iran nuclear deal," 6 Apr. 2021 Woodruff earned his 2020 opening day assignment with a breakthrough ’19 season, going 11-3 with a 3.62 ERA and making the National League all-star team. Tom Haudricourt, Milwaukee Journal Sentinel, "Brandon Woodruff ends 'curse of opening day starter' by getting second assignment for Brewers," 18 Mar. 2021 One of them is Chris Stapleton via his breakthrough 2015 album Traveller. David Chiu, Forbes, "Producer Dave Cobb On Collaborating With Chris Stapleton, Brandi Carlile, And Jason Isbell Ahead Of 2021 Grammys," 9 Mar. 2021 The Oregon Health Authority detected four breakthrough COVID-19 cases at least 14 days after vaccination. Chris Smith, BGR, "Here’s what you need to know about ‘breakthrough’ COVID-19 cases," 5 Mar. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'breakthrough.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of breakthrough


1915, in the meaning defined at sense 1


1946, in the meaning defined above

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Time Traveler for breakthrough

Time Traveler

The first known use of breakthrough was in 1915

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Statistics for breakthrough

Last Updated

6 May 2021

Cite this Entry

“Breakthrough.” Dictionary, Merriam-Webster, Accessed 12 May. 2021.

Style: MLA
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More Definitions for breakthrough



English Language Learners Definition of breakthrough

: a sudden increase in knowledge, understanding, etc. : an important discovery that happens after trying for a long time to understand or explain something
: a person's first important success


break·​through | \ ˈbrāk-ˌthrü How to pronounce breakthrough (audio) \

Kids Definition of breakthrough

: a sudden advance or successful development a breakthrough in medical research

Comments on breakthrough

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