expansion

American  

[ik-span-shuhn] / ɪkˈspæn ʃən /

noun

• expansions
  plural

1. the act or process of expanding.

2. the state or quality of being expanded.

3. the amount or degree of expanding.

4. an expanded, dilated, or enlarged portion or form of a thing.

   The present article is an expansion of one he wrote last year.

5. anything spread out; expanse.

6. Mathematics.

   1. the development at length of an expression indicated in a contracted form, as a 2 + 2 ab + b 2 for the expression (a +b ) 2 .

   2. any mathematical series that converges to a function for specified values in the domain of the function, as 1 + x + x 2 + … for 1/(1 −x ) when x < 1.

7. Machinery. that part of the operation of an engine in which the volume of the working medium increases and its pressure decreases.

8. an increase in economic and industrial activity (opposed to contraction).

9. additional content for a video game, card game, board game, etc., that significantly expands or alters the way the game is played.

   I really improved my deck with cards from the latest expansion.

   You can play the stand-alone expansion without ever buying the original game.

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expansion British  

/ ɪkˈspænʃən /

noun

1. the act of expanding or the state of being expanded

2. something expanded; an expanded surface or part

3. the degree, extent, or amount by which something expands

4. an increase, enlargement, or development, esp in the activities of a company

5. maths

   1. the form of an expression or function when it is written as the sum or product of its terms

   2. the act or process of determining this expanded form

6. the part of an engine cycle in which the working fluid does useful work by increasing in volume

7. the increase in the dimensions of a body or substance when subjected to an increase in temperature, internal pressure, etc

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expansion Scientific  

/ ĭk-spăn′shən /

1. An increase in the volume of a substance while its mass remains the same. Expansion is usually due to heating. When substances are heated, the molecular bonds between their particles are weakened, and the particles move faster, causing the substance to expand.

2. A number or other mathematical expression written in an extended form. For example, a ² + 2 ab + b ² is the expansion of (a + b) ².

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Other Word Forms

Derived Forms

• nonexpansion
  noun
• overexpansion
  noun
• preexpansion
  noun
• reexpansion
  noun
• self-expansion
  noun
• superexpansion
  noun
• antiexpansion
  adjective
• expansional
  adjective
• expansionary
  adjective

Inflected Forms

Nouns

• expansions
  plural

Etymology

Origin of expansion

First recorded in 1605–15; from Late Latin expānsiōn-, stem of expānsiō; equivalent to expanse + -ion

Explanation

Expansion is what happens when something becomes bigger or more extensive. If you enjoy good pastry, you will be excited by the expansion of the bakery, but be careful or you will also see the expansion of your waistline. The noun expansion is from the Latin word expansionem, which means a spreading out. Another definition for expansion is an elaboration or expanding upon something. If you're a teacher, you might be asked to give an expansion of the short talk you give students, "Homework Stinks: But Why We Need It Anyway" to parents at the school open house.

Example Sentences

See Examples For:

expansion expansions

Then came the New Deal’s dramatic expansion of the welfare state.

From The Wall Street Journal ● Sep. 16, 2026

Some researchers believe the committee's advice does not act as a barrier to Heathrow's expansion and will fail to achieve the reduction in planet-warming gases required.

From BBC ● Sep. 16, 2026

The government has an ongoing consultation which aims to judge any expansion against four tests - economy, climate, air quality and noise.

From BBC ● Sep. 16, 2026

An expansion could include air ambulance transport, cancer treatment, MRI scans and medications, EFF found.

From MarketWatch ● Sep. 15, 2026

In the course of that expansion, Austronesians came to occupy all habitable areas of those islands, from the seacoast to the interior, and from the lowlands to the mountains.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

After a decade of acquisitions and expansions by Spencer, Sharma is cutting output and focusing on key franchises she thinks have room to grow, like “Elder Scrolls” and “Halo.”

From The Wall Street Journal ● Sep. 12, 2026

Aggressive expansions typically come with plenty of risk: an immediate strain on resources, profit instability, and possibly outgrowing the existing business model.

From Slate ● Aug. 24, 2026

Looking forward, Qi said, "We are going to explore more satellite data and look for better understanding of the expansions."

From Science Daily ● Aug. 3, 2026

Some of those projects, including improvements and expansions to bus routes are still in the design phase.

From Los Angeles Times ● Jul. 31, 2026

Some of Greenberg’s subfamilies, and some groupings recognized by more-traditional linguists, may turn out to be legacies of New World population expansions driven in part by food production.

From "Guns, Germs, and Steel: The Fates of Human Societies" by Jared M. Diamond

Related Words

• development
• enlargement
• extension
• increase
• inflation
• spread