noun The edge of the paper, typically left blank when printing but sometimes used for annotations etc.
noun The edge or border of any flat surface.
noun The edge defining inclusion in or exclusion from a set or group.
noun A difference or ratio between results, characteristics, scores.
margin of victory
noun A permissible difference; allowing some freedom to move within limits.
margin of error
noun The yield or profit; the selling price minus the cost of production.
noun Collateral security deposited with a broker, to compensate the broker in the event of loss in the speculative buying and selling of stocks, commodities, etc.