margin - noun

the boundary line or the area immediately inside the boundary

an amount beyond the minimum necessary

the amount of collateral a customer deposits with a broker when borrowing from the broker to buy securities

(finance) the net sales minus the cost of goods and services sold

the blank space that surrounds the text on a page

a permissible difference; allowing some freedom to move within limits

margin - thesaurus

allowance   border   leeway   perimeter   tolerance