A substantial noninfringing use refers to the use made of a product that does not infringe the intellectual property rights of another. This alternative use must be significant enough so that it exceeds mere far-fetched or aberrant use.
There is no concrete test to determine if a use is substantial or not, however; the U.S. Supreme Court has held that elements to consider when determining substantiality include, "the use's frequency, the use's practicality, the invention's intended purpose, and the intended market."
- i4i Ltd. Partnership v. Microsoft Corp., 598 F.3d 831, 851 (Fed. Cir. 2010), aff'd, 131 S.Ct. 2238 (2011) (full-text).