Legal Definitions - implied license

An implied license is a permission, usually revocable, to perform an act that would otherwise be illegal. It arises from the conduct of the property owner regarding another person's use of the property, even though the owner has not expressly consented to the property's use. In a patent context, the circumstances surrounding the conduct give rise to an affirmative grant of consent or permission to infringe a patent's claims.

For example, if a patentee encourages the manufacture of infringing products, it may constitute an implied license to use the patent. Another example is when a patentee authorizes the sale or express grant of a license to a buyer, who then resells the license to a third party; the third party is the patentee's implied licensee.

Overall, an implied license is a royalty-free license that arises from the conduct of the property owner, even though there is no express consent to the property's use.