cairnn.[Gael. carn, gen. cairn, a heap: cf. Ir. & W. carn.]1. A rounded or conical heap of stones erected by early inhabitants of the British Isles, apparently as a sepulchral monument.()Now here let us place the gray stone of her cairn. (Campbell.)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.(C. Kingsley. Kane.)