break·through
ˈbrāk-ˌthrü 
plural breakthroughs
1
a
: a sudden advance especially in knowledge or technique
a medical breakthrough
b
: a person's first notable success
—often used before another noun
a breakthrough novel
the actress's breakthrough performance
2
a
: an act or instance of moving through or beyond an obstacle
a breakthrough in the talks between the region's leaders
a breakthrough agreement
b
: an instance of passing through a barrier or protection
The ice under the surface begins to deteriorate, increasing the risk of breakthroughs.—
Vicki Winger
Vicki Winger
specifically, medical
: infection occurring in someone who is fully vaccinated against an infectious agent
A vaccine breakthrough occurs when a person tests positive for COVID-19 two weeks after being fully vaccinated against the disease … —David Rasbach
—often used before another noun David Rasbach Two other CDC studies of breakthrough cases at nursing homes showed the vaccines protected residents, even when the virus spread through the homes. —Maura Dolan
Maura Dolan … the academy recently recommended that children receive two doses of the chicken pox vaccine, rather than just one, because the additional dose bolsters immunity and may help reduce breakthrough infection. —Maria Raven
Maria Raven 3
warfare
: an offensive military assault that penetrates and carries beyond a defensive line
broke through; broken through; breaking through; breaks through
: to make a breakthrough
Synonyms
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.
Recent Examples on the Web
Jared McCallister, New York Daily News, 31 Jan. 2025
Such a thesis conveniently overlooks that the breakthroughs of DeepSeek, OpenAI, and Anthropic were breakthroughs from disruptive startups, not national champions.
—Tom Wheeler, TIME, 30 Jan. 2025
Deborah Barfield Berry, USA TODAY, 1 Feb. 2025
But nothing has broken through like the funding memo, which sent state governments, nonprofits, schools, emergency workers and even some GOP officials scrambling to determine whether they'd be affected.
—Erin Doherty, Axios, 29 Jan. 2025
See all Example Sentences for breakthrough 
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Noun
However, a breakthrough in the casting of the Othello role took place 200 years ago.
—Jared McCallister, New York Daily News, 31 Jan. 2025
Such a thesis conveniently overlooks that the breakthroughs of DeepSeek, OpenAI, and Anthropic were breakthroughs from disruptive startups, not national champions.
—Tom Wheeler, TIME, 30 Jan. 2025
Verb
Thompson of Mississippi was in the Capitol four years ago when the attackers broke through barriers, forced their way in and tried to enter the House chamber.
—Deborah Barfield Berry, USA TODAY, 1 Feb. 2025
But nothing has broken through like the funding memo, which sent state governments, nonprofits, schools, emergency workers and even some GOP officials scrambling to determine whether they'd be affected.
—Erin Doherty, Axios, 29 Jan. 2025
See all Example Sentences for breakthrough
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Cite this Entry
“Breakthrough.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/breakthrough. Accessed 6 Feb. 2025.
Copy CitationKids Definition
breakthrough
noun
break·through
ˈbrāk-ˌthrü
: a sudden advance in knowledge or technique
a breakthrough in medical science
Medical Definition
breakthrough
noun
break·through
ˈbrāk-ˌthrü
: infection occurring in someone who is fully vaccinated against an infectious agent
—often used before another noun
breakthrough infections
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