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
The expansion of the role of pharmacies has meant that paying cash for generic drugs and services can also be cheaper at times.
—
Jasmine Laws, MSNBC Newsweek, 6 Nov. 2025
Researchers also discovered that dark energy had not always been dominant, appearing to begin its rule and start speeding up the expansion of the universe around 5 billion years ago, or roughly 9 billion years after the Big Bang.
—Robert Lea, Space.com, 6 Nov. 2025
His learnings from working with the mass retailer have played into this ethos of designing great wardrobing for the luxury woman, which has played into the designer’s global expansion.
—Emily Mercer, Footwear News, 5 Nov. 2025
The most successful entrepreneurs know how to turn data, relationships and reputation into engines for expansion.
—Rolling Stone Culture Council, Rolling Stone, 5 Nov. 2025
See All Example Sentences for expansion
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Jasmine Laws, MSNBC Newsweek, 6 Nov. 2025
Researchers also discovered that dark energy had not always been dominant, appearing to begin its rule and start speeding up the expansion of the universe around 5 billion years ago, or roughly 9 billion years after the Big Bang.
—Robert Lea, Space.com, 6 Nov. 2025
His learnings from working with the mass retailer have played into this ethos of designing great wardrobing for the luxury woman, which has played into the designer’s global expansion.
—Emily Mercer, Footwear News, 5 Nov. 2025
The most successful entrepreneurs know how to turn data, relationships and reputation into engines for expansion.
—Rolling Stone Culture Council, Rolling Stone, 5 Nov. 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 6 Nov. 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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