expansion
noun
ex·pan·sion
ik-ˈspan(t)-shən 
1
: expanse
2
: the act or process of expanding
territorial expansion
economic expansion
expansion of the universe
3
: the quality or state of being expanded
4
: the increase in volume of working fluid (such as steam) in an engine cylinder after cutoff or in an internal combustion engine after explosion
5
a
: an expanded part
b
: something that results from an act of expanding
the book is an expansion of a lecture series
6
: the result of carrying out an indicated mathematical operation : the expression of a function in the form of a series
Examples of expansion in a Sentence
The league is undergoing expansion.
the expansion of a lecture series into a book
This book is an expansion of a lecture series.
Recent Examples on the Web
This year, Spirit Halloween is extending over 20 contracts to support the expansion of Spirit Christmas, now entering its second year.
—
Victoria Moorwood, Cincinnati Enquirer, 23 Oct. 2025
Arcade said that as Chairman, Cory will lead the expansion of The Sidemen’s activities.
—Stewart Clarke, Deadline, 22 Oct. 2025
The outpost comes amid Salomon’s North America expansion, which includes a total of four brick-and-mortar shops with another shop expected to open by year’s end.
—Chris Gardner, HollywoodReporter, 22 Oct. 2025
At the Gateway Arch, a tram ride to the top offered sweeping views of the Mississippi River and downtown, while the museum below traced the city’s role in westward expansion.
—Okla Jones, Essence, 22 Oct. 2025
See All Example Sentences for expansion
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Victoria Moorwood, Cincinnati Enquirer, 23 Oct. 2025
Arcade said that as Chairman, Cory will lead the expansion of The Sidemen’s activities.
—Stewart Clarke, Deadline, 22 Oct. 2025
The outpost comes amid Salomon’s North America expansion, which includes a total of four brick-and-mortar shops with another shop expected to open by year’s end.
—Chris Gardner, HollywoodReporter, 22 Oct. 2025
At the Gateway Arch, a tram ride to the top offered sweeping views of the Mississippi River and downtown, while the museum below traced the city’s role in westward expansion.
—Okla Jones, Essence, 22 Oct. 2025
See All Example Sentences for expansion
Cite this Entry
“Expansion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/expansion. Accessed 29 Oct. 2025.
Copy CitationKids Definition
expansion
noun
ex·pan·sion
ik-ˈspan-chən
1
: the act of expanding
2
: the state of being expanded
3
: something expanded or a result of expanding
4
: the result of carrying out indicated mathematical operations
the expansion of (a + b)2 is a2 + 2ab + b2
Medical Definition
expansion
noun
ex·pan·sion
ik-ˈspan-chən
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