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
Stein touted the expansion as another example of North Carolina’s reputation as the furniture capital of the world.
—
Charlotte Observer, 17 Dec. 2025
Walmart plans to open 10 new Sam's Club outlets in China this year — its fastest expansion ever — and is on track to reach this target, with its 10th store opening in Guangzhou next week.
—Anniek Bao, CNBC, 17 Dec. 2025
Recent psychological studies on the experience of awe suggests that the expansiveness associated with this state is connected to our experience of time, and in particular with a feeling of temporal expansion.
—Literary Hub, 17 Dec. 2025
Halting the expansion of the illiberal international will require democracy’s defenders to rethink their approach.
—Nic Cheeseman, Foreign Affairs, 16 Dec. 2025
See All Example Sentences for expansion
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Charlotte Observer, 17 Dec. 2025
Walmart plans to open 10 new Sam's Club outlets in China this year — its fastest expansion ever — and is on track to reach this target, with its 10th store opening in Guangzhou next week.
—Anniek Bao, CNBC, 17 Dec. 2025
Recent psychological studies on the experience of awe suggests that the expansiveness associated with this state is connected to our experience of time, and in particular with a feeling of temporal expansion.
—Literary Hub, 17 Dec. 2025
Halting the expansion of the illiberal international will require democracy’s defenders to rethink their approach.
—Nic Cheeseman, Foreign Affairs, 16 Dec. 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 20 Dec. 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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