The Hound of the Baskervilles vocabulary

1. A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument.

2. A pile of stones heaped up as a landmark, or to arrest attention, as in surveying, or in leaving traces of an exploring party, etc.

---

In modern times, cairns are often erected as landmarks, a use they have had since ancient times. However, since prehistory, they have also been built and used as burial monuments; for defense and hunting; for ceremonial purposes, sometimes relating to astronomy; to locate buried items, such as caches of food or objects; and to mark trails, among other purposes.

Cairns are used as trail markers in many parts of the world, in uplands, on moorland, on mountaintops, near waterways and on sea cliffs, as well as in barren deserts and tundra. They vary in size from small stone markers to entire artificial hills, and in complexity from loose conical rock piles to delicately balanced sculptures and elaborate feats of megalithic engineering. Cairns may be painted or otherwise decorated, whether for increased visibility or for religious reasons.