View synonyms for expansion


[ ik-span-shuhn ]


  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 ( 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.


/ ɪkˈspænʃən /


  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
“Collins English Dictionary — Complete & Unabridged” 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012


/ ĭk-spănshən /

  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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Derived Forms

  • exˈpansionary, adjective
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Other Words From

  • ex·pansion·al adjective
  • anti·ex·pansion adjective
  • nonex·pansion noun
  • over·ex·pansion noun
  • preex·pansion noun
  • reex·pansion noun
  • self-ex·pansion noun
  • super·ex·pansion noun
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Word History and Origins

Origin of expansion1

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

Still, the expansion in testing alone can’t fully explain the current case uptick, at least not in every country.

From Vox

China is a great nation, and we should hope for the continued expansion.

Many factors are driving the violent expansion of this years' wildfires.

A few days later, Pfizer announced plans to expand the number of participants enrolled in its clinical trials by the thousands but gave little details on the expansion.

In April, there was an hourlong “Election Administration Forum Conference Call” that covered, in part, the expansion of mail-in voting and “ways to message these concerns to your constituents,” according to the invitation.

Missy Suicide, formerly known as Selena Mooney, is in New York for a series of brand-expansion meetings.

He recently put up $50 million for half the cost of the Kennedy Center expansion, where he is chairman of the board.

Tellingly, but not coincidentally, the greatest expansion of Medicaid has occurred in Deep Blue America.

Even the most adamant Obamacare opponent must acknowledge, as Kasich has, that its coverage expansion has helped some people.

He also has backed Medicaid expansion and a state-run exchange under Obamacare.

This engine only took steam during the first quarter of its stroke, the remaining three-quarters were by the expansion.

This most simple steam-engine combined in the greatest degree the two elements of expansion and momentum.

The coal burnt under the boiler gives a duty of sixty-six millions, or an expansion of 60 per cent.

Every step which she took toward relieving herself from obligations added to her strength and expansion as an individual.

The settlement no doubt was influenced by the imminence of a large expansion of policy—the ill-starred Irish expedition.