expansion

noun

ex·​pan·​sion ik-ˈspan(t)-shən 

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 

adjective

Synonyms

• accretion
• accrual
• addendum
• addition
• augmentation
• boost
• gain
• increase
• increment
• more
• plus
• proliferation
• raise
• rise
• step-up
• supplement
• uptick

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

The funds will be used to bankroll the expansion of the flagship FPSO business as well as a growing green energy portfolio under Yinson Renewables, a subsidiary that has solar and wind power projects in multiple countries. —Jonathan Burgos, Forbes.com, 17 Apr. 2025

This also includes the expansion of the company’s Solomeo headquarters, already partly operational in 2025, and the production capacity for the 10-year project running from 2024 to 2033. —Sofia Celeste, Footwear News, 16 Apr. 2025

Then, after the Biden administration granted TPS for Venezuelans, Rubio requested an expansion so more Venezuelans would qualify. —Verónica Egui Brito, Miami Herald, 16 Apr. 2025

The expansion comes after Party City filed for bankruptcy last year and closed its 700 US stores in late February. —Jordan Valinsky, CNN Money, 16 Apr. 2025

Word History

First Known Use

1611, in the meaning defined at sense 1

Phrases Containing expansion

• expansion card
• expansion slot

Rhymes for expansion

• mansion
• scansion

Kids Definition

expansion

noun

ex·​pan·​sion ik-ˈspan-chən 

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 

1

: the act or process of expanding

2

: the quality or state of being expanded