<p><strong>Noun</strong></p><ul><li>the act or process of expanding.</li><li>the state or quality of being expanded.</li><li>the amount or degree of expanding.</li><li>an expanded, dilated, or enlarged portion or form of a thing: The present article is an expansion of one he wrote last year.</li><li>anything spread out; expanse.</li><li>Mathematics: the development at length of an expression indicated in a contracted form, as a² + 2ab + b² for the expression (a + b)².</li><li>any mathematical series that converges to a function for specified values in the domain of the function, as 1 + x + x² + … for 1/(1 − x) when x &lt; 1.</li><li>Machinery: that part of the operation of an engine in which the volume of the working medium increases and its pressure decreases.</li><li>an increase in economic and industrial activity (contraction).</li><li>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.</li><li>You can play the stand-alone expansion without ever buying the original game.</li></ul>