Definition of "cairn"

cairn

/kɛən/

noun
plural cairns
1. A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument.
  Quotations
  "Now here let us place the gray stone of her cairn: / Why speak ye no word!"—said Glenara the stern.
  1826, Thomas Campbell, “Glenara”, in The Poetical Works of Thomas Campbell, page 105
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.
  Quotations
  After fifteen minutes of this we were glad to reach a high saddle on which former travellers had piled little cairns of commemoration and thankfulness.
  1926, T. E. Lawrence, Seven Pillars of Wisdom, New York: Anchor, published 1991, page 180
3. A cairn terrier.