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.
The plan includes a $330 million manufacturing expansion, additional launch pads, and new facilities for payload processing and booster refurbishment. — Aamir Khollam, Interesting Engineering, 17 Oct. 2026 Golden State is looking to become the fastest expansion team in league history to win a championship as the Valkyries are only in their second year. — ABC News, 17 Oct. 2026 The commissioner reportedly mentioned Mexico City as an expansion alternative in a meeting with the board of governors last month. — Matt Calkins Outkick, FOXNews.com, 17 Oct. 2026 During her State of the Union address on 16th September, President von der Leyen committed to overhauling single market rules by the end of next year and advancing EU Inc to streamline cross-border expansion. — Sophie Dembinski, Fortune, 16 Oct. 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

Browse Nearby Words

Cite this Entry

“Expansion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/expansion. Accessed 22 Oct. 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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