cairn (n.) Look up cairn at Dictionary.com
"large, conical heap of stone," especially of the type common in Scotland and Wales and also found elsewhere in Britain, 1530s, from Scottish carne, akin to Gaelic carn "heap of stones, rocky hill" and Gaulish karnon "horn," perhaps from PIE *ker-n- "highest part of the body, horn," thus "tip, peak" (see horn (n.)).