Revenue (Total Revenue)
Plain definition
The total money a firm receives from selling its output: price × quantity sold (TR = P × Q).
In economics
Revenue is the starting point of all profit calculations — accounting profit subtracts explicit costs, economic profit subtracts all opportunity costs. The shape of the revenue curve depends on market structure: it is a straight line under perfect competition (the firm is a price taker) but rises then falls under monopoly as higher output requires lower prices.
Example
Selling 1,000 units at 25,000.
Common confusion
Revenue is confused with profit. Revenue is the gross inflow before any costs are subtracted; profit is what remains after costs. A firm can have record revenue and still make a loss if costs are higher.