OPPORTUNITY COST: The highest valued alternative foregone in the pursuit of an activity. This is a hallmark of anything dealing with economics--and life for that matter--because any action that you take prevents you from doing something else. The ultimate source of opportunity cost is the pervasive problem of scarcity (unlimited wants and needs, but limited resources). Whenever limited resources are used to satisfy one want or need, there are an unlimited number of other wants and needs that remain unsatisfied. Herein lies the essence of opportunity cost. Doing one thing prevents doing another. See also | economics | scarcity | unlimited wants and needs | limited resources | resources | scarce resource | free resources | production possibilities | production possibilities frontier | law of increasing opportunity cost | value | satisfaction | consumption | production | economic cost | accounting cost | total cost |