Source: Image of gears, public domain, http://www.clker.com/clipart-2950.html; Image of cost and revenue curves, creative commons, http://en.wikipedia.org/wiki/File:Profit_max_total_small.svg
Total revenue minus total cost.
Rise over run; change in the value of the y-axis variable relative to a change in the x-axis variable.
All variable and fixed costs associated with production which includes opportunity cost.
All sales generated by a firm from the sale of a product or service.