# expansion

Pronunciation: say "ik-SPAN-shuhn" /ɪkˈspænʃən/

## Noun

1. The process of becoming larger or making something larger, or a single case of this.
   - Simple: The act of getting bigger or spreading out over more space.
   - _Rapid expansion of the company strained its supply chain._
   - _Scientists measured the gas's expansion as the temperature rose._
2. A phase of the business cycle in which economic activity, such as output and employment, keeps growing, from a low point to the next peak.
   - Simple: A time when a country's economy grows and people buy and sell more.
   - _The decade-long expansion raised household incomes across the region._
   - _Economists debate whether the current expansion can survive rising interest rates._
3. Ellipsis of expansion pack. — Ellipsis of expansion pack.
   - Simple: Short for expansion pack: a package of extra content for an existing game.
   - _The studio announced an expansion that doubles the size of the game's map._
   - _Veteran players complained that the expansion broke several older quests._
4. A newly added section or wing built onto an existing structure.
   - Simple: A new part added to a building to make it bigger.
   - _Visitors now enter through the glass expansion on the east side of the library._
   - _The museum's new expansion, a two-story glass wing, houses its modern art collection._
5. In algebra, the process of writing out an expression as an equal but longer sum of terms, as when brackets are multiplied out.
   - Simple: Rewriting a mathematical expression as a longer sum with the same value.
   - _The expansion of (x + 1)² gives x² + 2x + 1._
   - _Students practiced expansion of bracketed expressions before learning to factor them._
6. The full form that an abbreviation or acronym stands for, or the act of writing it out in full.
   - Simple: The full words that a short form or set of letters stands for, or writing those words out.
   - _House style calls for expansion of all initialisms on first mention._
   - _Medical papers usually give the expansion of an acronym like 'MRI' the first time it appears._

## Noun

7. That which has been expanded or spread out; an expanse or extended surface. *(dated)*
   - Simple: A wide, open space or surface that spreads out far.

## Other meanings

- (noun) Thermal expansion as a property of a material: how much it grows as it heats, often given as the fraction of its length gained per degree.
- (noun) In geometry, an operation on a figure with flat faces that moves the faces apart from the center and fills the gaps with new faces.
- (noun) The continued action of steam in a cylinder after its supply from the boiler has been cut off, during which it goes on exerting pressure on the moving piston.

## Origin

English borrowed it from French expansion, which goes back to Latin expānsiō. Looked at from English alone, it splits into expand plus the suffix -sion.

Source: DictionaryAI, https://dictionaryai.com/define/expansion (written from Wiktionary data, CC BY-SA 4.0: https://creativecommons.org/licenses/by-sa/4.0/).