Gross Profit (also called gross margin or gross profit rate) is the difference between revenue and cost. This is how much money you have left after you have subtracted the direct costs from the selling price. It identifies the amount available to cover other operating expenses.
Generally, it is calculated as the selling price of an item, less the cost of goods sold (production or acquisition costs, essentially).
Income (aka Revenue) -Direct Costs = Gross Profit (aka Gross Profit Margin)