Of, or pertaining to, the Dutch province of Friesland, the Frisian people or the Frisian language
an alternate name for the West Frisian language, widely used in informal speech and writing, or where context makes the meaning unambiguous. (Compare: America, when synonymous with the United States of America.)
the language group (West Frisian, Saterland Frisian, and North Frisian) spoken by many people in the Dutch province of Friesland, some people in Northern Germany and in some parts of Denmark, mainly west coast