overflow
Americanverb (used without object)
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to flow or run over, as rivers or water.
After the thaw, the river overflows and causes great damage.
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to have the contents flowing over or spilling, as an overfull container.
Stop pouring or your glass is going to overflow.
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to pass from one place or part to another as if flowing from an overfull space.
The population overflowed into the adjoining territory.
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to be filled or supplied with in great measure.
a heart overflowing with gratitude; a region overflowing with orchards and vineyards.
verb (used with object)
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to flow over; flood; inundate.
The river overflowed several farms.
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to flow over or beyond (the brim, banks, borders, etc.).
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to cause to overflow.
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to flow over the edge or brim of (a receptacle, container, etc.).
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to fill to the point of running over.
noun
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an overflowing.
the annual overflow of the Nile.
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something that flows or runs over.
to carry off the overflow from a fountain.
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a portion crowded out of an overfilled place.
to house the overflow of the museum's collection in another building.
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an excess or superabundance.
an overflow of applicants for the job.
- Synonyms:
- glut, flood, plethora, surplus, overabundance
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an outlet or receptacle for excess liquid.
The tank is equipped with an overflow.
verb
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to flow or run over (a limit, brim, bank, etc)
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to fill or be filled beyond capacity so as to spill or run over
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to be filled with happiness, tears, etc
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(tr) to spread or cover over; flood or inundate
noun
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overflowing matter, esp liquid
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any outlet that enables surplus liquid to be discharged or drained off, esp one just below the top of a tank or cistern
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the amount by which a limit, capacity, etc, is exceeded
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computing a condition that occurs when numeric operations produce results too large to store in the memory space assigned to it
Other Word Forms
Etymology
Origin of overflow
before 900; Middle English overflowen, Old English oferflōwan. See over-, flow
Explanation
To overflow is to go beyond filling something with a liquid, so that it gushes over the edges. During heavy rainstorms, rivers sometimes overflow their banks and flood the surrounding land. Bathwater will overflow the tub if you don't turn the water off, and if you keep pouring coffee after your cup is full, it will also overflow. Literal overflowing involves liquid, but you can also use this verb to mean "fill a container" or "fill with feeling." So your arms can overflow with flowers, and your heart can overflow with happiness. The Old English root is oferfleow, "flood" or "inundate."
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
After ChatGPT launched, Stack Overflow, the world’s largest online community for software developers, saw web traffic drop by roughly 12 percent and question volumes fall across its most popular topics.
From Slate • Apr. 12, 2026
We learned a lot from German Wikipedia and Stack Overflow about how A.I. restrictions can be implemented and what constitutes a reasonable exception.
From Slate • Apr. 1, 2026
And at the end of last year Water UK - the industry body - launched the National Storm Overflow Hub where almost real-time discharges can be seen across all of England's overflow points.
From BBC • Jul. 20, 2025
Overflow from nearby Lake Success upstream has already flooded dozens of homes in the area.
From Los Angeles Times • Mar. 17, 2023
Amalgamation Without Overflow": "Recent experiments at the Ballarat School of Mines have proved that a deliverance from difficulties is at hand from an unexpected quarter.
From Getting Gold: a practical treatise for prospectors, miners and students by Johnson, J. C. F. (Joseph Colin Frances)
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
