What is "slupnica"

http://www.slupnica.pl.tl Słupnica is a village in the administrative district of Gmina Biskupiec, within Nowe Miasto County, Warmian-Masurian Voivodeship, in northern Poland. It lies approximately north-west of Biskupiec, north-west of Nowe Miasto Lubawskie, and west of the regional capital Olsztyn.