An act, process, or instance of expanding, such as the fractional change in unit length per unit length per unit temperature change, a new addition to a building, a product used with a previous product, an expanse or extended surface, the operation of steam in a cylinder after its communication with the boiler has been cut off, the act of replacing a short name with a longer synonymous name in writing, editing, or audio content, and a short term for an expansion pack in video games.