Definition of "expansion"

An act, process, or instance of expanding.

1. The fractional change in unit length per unit length per unit temperature change.  examples

2. (building) A new addition.  examples

3. A product to be used with a previous product.  examples

4. That which is expanded; expanse; extended surface.  quotations  examples

   Quotations

   • Mother of mighty Rome's imperial line, / Delight of man, and of the powers divine, / Venus, all-bounteous queen! whose genial power / Diffuses beauty in unbounded store / Through seas, and fertile plains, and all that lies / Beneath the starred expansion of the skies.

     a. 1804, James Beattie, “The Beginning of the First Book of Lucretius”, in The Poetical Works of James Beattie (The Aldine Edition of the British Poets), London: Bell and Daldy […], published 1866, pages 170–171

5. (steam engines) The operation of steam in a cylinder after its communication with the boiler has been cut off, by which it continues to exert pressure upon the moving piston.  examples

6. The replacement of a short name (e.g., acronym, initialism, alphanumeric symbol, abbreviation) with the longer name that is synonymous with it, as when spelling out acronyms to ensure clarity for a general audience.

   1. The string of text thus substituted.  examples

7. (video games) Short for expansion pack.  examples