A threshold stone or sill stone (German: Schwellenstein) is a rectangularly dressed stone slab that forms part of the entrance of megalithic tombs of the Funnelbeaker culture, normally those with a passage. The red sandstone slab, up to 0.1 metres thick, was buried in the ground to a depth of 0.2 metres at the entrance to the chamber. Cultural sites of other types, such as Domus de Janas, also have a clear partition between the passage and the ante-chamber or main chamber.