Introduction - If you have any usage issues, please Google them yourself
In mathematics, the Euclidean distance or Euclidean metric is the ordinary (i.e. straight-line) distance between two points in Euclidean space. With this distance, Euclidean space becomes a metric space. The associated norm is called the Euclidean norm. Older literature refers to the metric as Pythagorean metric. A generalized term for the Euclidean norm is the L2 norm or L2 distance.