Varifold
MEASURE-THEORETIC GENERALIZATION OF THE CONCEPT OF A DIFFERENTIABLE MANIFOLD, BY REPLACING DIFFERENTIABILITY REQUIREMENTS WITH THOSE PROVIDED BY RECTIFIABLE SETS
In mathematics, a varifold is, loosely speaking, a measure-theoretic generalization of the concept of a differentiable manifold, by replacing differentiability requirements with those provided by rectifiable sets, while maintaining the general algebraic structure usually seen in differential geometry. Varifolds generalize the idea of a rectifiable current, and are studied in geometric measure theory.