Online Resource centre of U.S. Department of the Treasury explained that a license is an authorization from OFAC to engage in a transaction that otherwise would be prohibited. There are two types of licenses: general licenses and specific licenses.
A general license authorizes a particular type of transaction for a class of persons without the need to apply for a license.
A specific license is a written document issued by OFAC to a particular person or entity, authorizing a particular transaction in response to a written license application.
Persons engaging in transactions pursuant to general or specific licenses must make sure that all conditions of the licenses are strictly observed.
OFAC's regulations may contain statements of OFAC's specific licensing policy with respect to particular types of transactions.