Margin
Part of speech: noun
Definition: The edge of the paper that remains blank. The yield or profit; the selling price minus the cost of production. A permissible difference; allowing some freedom to move within limits, as a margin of error.
Part of speech: verb
Definition: To add a margin to.
Example sentence: In this quest to seek and find God in all things, there is still an area of uncertainty. There must be. If a person says that he met God with total certainty and is not touched by a margin of uncertainty, then this is not good.
Perimeter
Part of speech: noun
Definition: The sum of the distance of all the lengths of the sides of an object.The outer limits of an area. See Synonyms at circumference.The length of such a boundary.A fortified strip or boundary usually protecting a military position.