[? cach ar racas, rhacas, bnth. ff. l. y S. 'rag'] Y gwrymiau a'r gramen o faw sy'n hel ar liniau pobl sy'n gweithio ar eu gliniau neu ar liniau plant wrth chwarae: caked dirt which forms on the knees of those who kneel while working or on the knees of children at play.