metric

1. A way to measure something; a means of deriving a quantitative measurement or approximation for otherwise qualitative phenomena (especially used in engineering). · What metric should be used for performance evaluation?· What are the most important metrics to track for your business?
2. A function which satisfies a particular set of formal conditions, created to generalize the notion of the distance between two points. Formally, a real-valued function d on M×M, where M is a set, is called a metric if (1) d(x,y)=0 if and only if x=y, (2) d(x,y)=d(y,x) for all pairs (x,y), and (3) d obeys the triangle inequality.
3. A metric tensor.

Plural metrics