In mathematics:

Metric system, a system of units developed in France in the 18th century

SI, or Système International, the international system of units since 1960, a subset of the former

Metre (poetry), the linguistic sound patterns of a verse

Metric (band), a Canadian indie rock band

Metre (music), a measurement of beats in music

Software metrics, a measure of some property of a piece of software or its specifications

Metric tensor, a symmetric tensor of rank 2 used to measure distance

Metrics, a system of parameters that are measured

Metrics (networking), set of properties of a communication path

Metric (mathematics), an abstraction of the notion of distance in a metric space

Norm (mathematics), an abstraction of the notion of size in a normed vector space