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
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
Allbusiness, Forbes.com, 8 May 2025
As with the oil and gas industry, the IEA said that no technological breakthroughs are required to cut emissions from coal.
—Jeff Young, MSNBC Newsweek, 8 May 2025
Philip Elliott, Time, 8 May 2025
Previous studies had already revealed the presence of thorium consistent with KREEP impact melt along the floor of the basin, suggesting that the mantle material may have broken through the crust during the impact.
—Nola Taylor Tillman, Space.com, 5 May 2025
See All Example Sentences for breakthrough
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.
Noun
Academic labs and early-stage biotech companies—where tomorrow’s breakthroughs are born—depend on flexible, reliable suppliers.
—Allbusiness, Forbes.com, 8 May 2025
As with the oil and gas industry, the IEA said that no technological breakthroughs are required to cut emissions from coal.
—Jeff Young, MSNBC Newsweek, 8 May 2025
Verb
The stealth contender broke through the byzantine Vatican politics and may yet break Washington’s understanding of how the Catholic machinery operates around the globe.
—Philip Elliott, Time, 8 May 2025
Previous studies had already revealed the presence of thorium consistent with KREEP impact melt along the floor of the basin, suggesting that the mantle material may have broken through the crust during the impact.
—Nola Taylor Tillman, Space.com, 5 May 2025
See All Example Sentences for breakthrough
Cite this Entry
“Breakthrough.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/breakthrough. Accessed 14 May. 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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share