expansion

noun

ex·​pan·​sion ik-ˈspan(t)-shən How to pronounce expansion (audio)
Synonyms of expansionnext
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
expansional
ik-ˈspan(t)-sh(ə-)nəl How to pronounce expansion (audio)
adjective

Synonyms of expansion

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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 only blot on an otherwise solid opening week for the World Cup expansion loyalists. — Anantaajith Raghuraman, New York Times, 5 July 2026 The dramatic expansion of the city’s early childhood system will require a similarly rapid scaling of its workforce. — Cayla Bamberger, New York Daily News, 4 July 2026 Playhouse on Park often has to scale down large musicals for its 160-seat theater, but in this case the close-up party atmosphere feels like an expansion. — Christopher Arnott, Hartford Courant, 5 July 2026 The dispute has become part of a broader national debate over the rapid expansion of data centers to support growing demand for cloud computing and artificial intelligence systems. — Julianna Bragg, CNN Money, 5 July 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

Phrases Containing expansion

Rhymes for expansion

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Browse Nearby Words

expansile
expansion
expansional
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Cite this Entry

“Expansion.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/expansion. Accessed 7 Jul. 2026.

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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

Nglish: Translation of expansion for Spanish Speakers

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