piecewise linear

Short definition from Wiktionary

Adjective

1. 1
   Equal to a sum of finitely many linear functions, each defined on a convex polytope: said of functions between vector spaces
2. 2
   Having a defining atlas such that there is a piecewise linear homeomorphism between any pair of intersecting atlas charts: said of manifolds
3. 3
   Alternative spelling of piecewise linear.