Webster’s Revised Unabridged Dictionary · 1913
Rewel bone
Rew′el bone′ (rṳ′ĕl bōn′). [Perh. from F. rouelle, dim. of roue a wheel, L. rota.] An obsolete phrase of disputed meaning, — perhaps, smooth or polished bone.
His saddle was of rewel boon. Chaucer.