the.com/stone cairn

means A human-made pile of stacked stones, often marking a trail, a grave, a summit, or a boundary.

from From Scottish Gaelic càrn, meaning 'heap of stones' — a word that passed into English largely unchanged because the thing itself needed no translation. Cairns appear across cultures and millennia, from Neolithic burial mounds to modern hikers' trail markers, which is part of why the word feels so old: it names one of the few gestures nearly every human culture independently invented.