The
Metric System is a common term for the
International System of Units.
In
mathematics, a
metric (also called
distance metric) is an abstraction of the notion of
distance; it is used to define
metric spaces. The article on
metric spaces contains a detailed discussion of the topic.
The term is also used in a slightly different context: the structure that turns a manifold into a Riemannian manifold is called a metric. Such a metric allows to introduce geodesics and to measure distances and angles on the manifold.
