Margin

From Latin margin-, oblique stem of margo ("edge, brink, border, margin").

Full definition of margin

(plural margins)

1913, w, Lord Stranleigh Abroad Chapter 4, Nothing could be more business-like than the construction of the stout dams, and nothing more gently rural than the limpid lakes, with the grand old forest trees marshalled round their margins like a veteran army that had marched down to drink, only to be stricken motionless at the waterâ€™s edge.
Schuster Hepaticae V|7The lobule margins, furthermore, are arched away from the lobe, with the consequence that (when fully inflated) the abaxial leaf surface forms the interior lining of the lobule.

(figuratively) The edge defining inclusion in or exclusion from of a set or group.

1999, Pierre FranÃ§ois, ''Inlets of the Soul: Contemporary Fiction in English and the Myth of the Fall, page 186,As far as space is concerned, Mary Lamb finds herself at the farthest margin of society - among tramps - when the novel begins.

2012, April 15, Phil McNulty, Tottenham 1-5 Chelsea, Chelsea will point to that victory margin as confirmation of their superiority - but Spurs will complain their hopes of turning the game around were damaged fatally by Atkinson's decision.

A permissible difference; allowing some freedom to move within limits.margin of error
(finance) The yield or profit; the selling price minus the cost of production.
(finance) Collateral security deposited with a broker to secure him from loss on contracts entered into by him on behalf of his principial, as in the speculative buying and selling of stocks, wheat, etc.