expansion

noun

ex·​pan·​sion ik-ˈspan(t)-shən How to pronounce expansion (audio)
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
expansional adjective

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.
But recent court filings suggest the company’s expansion may have been accompanied by financial hardship. David Hudnall, Kansas City Star, 12 Mar. 2025 The federal government pays 90% of the costs of Idaho’s Medicaid expansion. Sarah Cutler and, Idaho Statesman, 12 Mar. 2025 The game’s success has lead to multiple expansions and placement on retail shelves next to board game classics like Monopoly and Clue. Rob Wieland, Forbes, 12 Mar. 2025 For those unfamiliar with Pokémon cards, an Elite Trainer Box is a special collector's box containing a variety of cards, packs, and accessories designed for fans looking to enhance their collection or dive into a new expansion. Faisal Kutty, Newsweek, 12 Mar. 2025 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 16 Mar. 2025.

Kids Definition

expansion

noun
ex·​pan·​sion ik-ˈspan-chən How to pronounce expansion (audio)
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 How to pronounce expansion (audio)
1
: the act or process of expanding
2
: the quality or state of being expanded

More from Merriam-Webster on expansion

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