The Windic March (German: Windische Mark) was a medieval frontier march of the Holy Roman Empire, roughly corresponding to the Lower Carniola (Dolenjska) region in present-day Slovenia. In Slovenian historiography, it is sometimes known as Slovenian March (Slovene: Slovenska marka or Slovenska krajina).
The name Windic is derived from Wends (German: Wenden), the name for Western Slavs settling in the Germania Slavica contact zone. The medieval German term Windisch referred to the Slovene language; it should not to be confused with Wendische, the historic German term for the Sorbian-speaking population in Lusatia. In the 6th and 7th century the term Windische was used by Bavarian settlers to refer to the Slavic population in the East Alpine principality of Carantania, who were called Veneti in Latin sources after the ancient Adriatic Veneti tribes. However, it should be noted that the medieval geographic term windisches Land referred exclusively to the Croatian region of Slavonia.
The Chronicle of Fredegar mentions "Sclavos coinomento Winedorum" in 623.Samo's tribal union included the Windic March (Marca Vinedorum) of Duke Valuk (Wallucus Dux), located in the Eastern Alps, in 631.