That part of the cost of any output that could be saved by not producing it. Some costs are clearly not avoidable, for example capital costs. Other costs might on first inspection appear to be avoidable, but may actually not be. For example, ceasing production would save on fuel, materials, and labour; but fuel and materials may be bought on long-term contracts, and employees laid off may be entitled to pay in lieu of notice. Thus these costs, too, may not be avoidable in the short run.