Definition: Economic Game

I wrote the following recently as part of a discussion on boardgamegeek:

An economic game implements an economy which the players either significantly create or engage in during the course of play. An economy consists of one or more marketplaces in which one or more currencies are exchanged either for goods/resources or other (potential) currencies, and in which the cycle of inputs to conversions to outputs is or can be self-sustaining. A currency is merely a granular entity with variable value which is conceived of as a trade item for other currencies or value goods.