cairn

Short definition from Wiktionary

Noun

1. 1
   A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument.
2. 2
   A pile of stones heaped up as a landmark, to guide travelers on land or at sea, or to arrest attention, as in surveying, or in leaving traces of an exploring party, etc.
3. 3
   A cairn terrier.