'''Distance''' is a [[numerical]] description of how far apart objects are. In [[physics]] or everyday [[discussion]], distance may refer to a [[physical]] length, or an estimation based on other criteria (e.g. "two counties over"). In [[mathematics]], a distance [[function]] or metric is a generalization of the [[concept]] of physical distance. A metric is a function that behaves according to a specific set of rules, and provides a concrete way of describing what it means for elements of some space to be "close to" or "far away from" each other. | '''Distance''' is a [[numerical]] description of how far apart objects are. In [[physics]] or everyday [[discussion]], distance may refer to a [[physical]] length, or an estimation based on other criteria (e.g. "two counties over"). In [[mathematics]], a distance [[function]] or metric is a generalization of the [[concept]] of physical distance. A metric is a function that behaves according to a specific set of rules, and provides a concrete way of describing what it means for elements of some space to be "close to" or "far away from" each other. |