Proper noun
(historical) The part of the historical region of Frisia between the Vlie and Lauwers, covering the present-day province of Frisia, the Ommelanden, and present-day West-Friesland in the province of North Holland.
The present-day Dutch province of Frisia (Fryslân). (Usually used in an international context.)
A region in the Dutch province of North Holland bordering the IJsselmeer (West-Friesland).
(historical) The part of the historical region of Frisia west of the Vlie, covering parts of Holland and Zeeland.
(uncommon) The western part of the present-day Dutch province of Frisia (Fryslân).
Source: en.wiktionary.org