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 Valkyries made history in their inaugural season, becoming the first WNBA expansion team to reach the playoffs in its debut year. — Emma Burleigh, Fortune, 24 Oct. 2026 Meanwhile, Abbott had opposed the expansion of key programs, such as Medicaid. — Stephania Taladrid, New Yorker, 24 Oct. 2026 Manufacturing for rising electricity demand The new funding will support Peak’s manufacturing expansion as utilities add storage alongside renewable generation and electricity demand grows. — Atharva Gosavi, Interesting Engineering, 24 Oct. 2026 The company has not said whether the expansion will require more robots on Philadelphia sidewalks or whether its existing fleet will handle the additional orders. — Kurt Knutsson, FOXNews.com, 24 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 27 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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