In business usage, the excess of total revenue over total cost during a specific period of time.
In economics, profit is the excess over the returns to capital , land , and labour . Since these resources are measured by their opportunity cost s, economic profit can be negative. There are various sources of profit: an innovator who introduces a new production technique can earn entrepreneurial profits; changes in consumer tastes may bring some firms windfall profits; or a firm may restrict output to prevent prices from falling to the level of costs (monopoly profit).