Equivalent means anything which is comparable in content, substance, material, denomination, number, quality etc., but not identical. Under patent law, an invention against an equivalent may be challenged for infringement by a patent holder (patentee). Doctrine of equivalents means similarity or resemblance among the elements of an existing infringed patent and alleged invention. Under the doctrine, the product or process may not literally infringe the express terms of a patent claim.
[Last updated in July of 2021 by the Wex Definitions Team]