Synonyms of expansion
1
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
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.
In July 2026, Ukrainian reports indicated a further expansion of the Gerbera’s operational roles. Vikram Mittal, Forbes.com, 2 Aug. 2026 This expansion adds 500 megawatts of direct current (MWdc) to the local power grid, bringing the facility’s total operating capacity close to 1 gigawatt direct current (GWdc). Aman Tripathi, Interesting Engineering, 2 Aug. 2026 But the law remained intact when Micron negotiated its expansion plans nearly 15 years later. Mark Dee august 2, Idaho Statesman, 2 Aug. 2026 American technology billionaire Nikesh Arora is in talks to buy the new London team in the NBA’s European expansion, according to sources with knowledge of the deal who spoke on the condition of anonymity because the sale talks are still ongoing. Amelie Claydon, New York Times, 2 Aug. 2026 See All Example Sentences for expansion

Word History

First Known Use

1611, in the meaning defined at sense 1

Time Traveler
The first known use of expansion was in 1611

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Cite this Entry

“Expansion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/expansion. Accessed 5 Aug. 2026.

Kids Definition

expansion

noun
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
1
: the act or process of expanding
2
: the quality or state of being expanded

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