Standing stone: a large block of stone set upright; a menhir, monolith.
Menhir is actually the French word for "standing stone". It comes from Breton men (stone) and hir (long). This is an example of a standing stone circle, taken yesterday in Avebury.
The most famous example of standing stones in the UK is Stonehenge, a stone’s throw away (ahem), in the Salisbury plain.
French and English have a different word for stones which form a table (although it is more commonly used in French), namely "dolmen". This comes from the Breton taol, tol (table) and men (stone). It is not very surprising that these Breton words were borrowed in French and English; Britanny is the region of France where one may find well-preserved stone circles, in Carnac for example.