ruel-bone
/ˈruːəlbəʊn/noun
Ivory, probably from the tusk of a walrus or narwhal; = ruel; (also) a piece of ivory. Hence occasionally as adjective: made of this. Now archaic and literary.
- Probably independently revived from Middle English use by J. R. R. Tolkien in the 20th cent.; and hence in later fantasy writing..
Origin
Middle English; earliest use found in Gregorius. From ruel + bone.