Definition of "crag"

"Have, then, thy wish!"—he whistled shrill, / And he was answered from the hill; / Wild as the scream of the curlieu, / From crag to crag the signal flew.

1810, Walter Scott, “Canto V. The Combat.”, in The Lady of the Lake; […], Edinburgh: […] [James Ballantyne and Co.] for John Ballantyne and Co.; London: Longman, Hurst, Rees, and Orme, and William Miller, stanza IX, page 202

Break, break, break, / At the foot of thy crags, O Sea! / But the tender grace of a day that is dead / Will never come back to me.

1835, Alfred Tennyson, “‘Break, Break, Break’”, in Poems. […], volume II, London: Edward Moxon, […], published 1842, stanza 3, page 229