Webster's Revised Unabridged Dictionary · 1913

Amianthus

Amianthus ({not transcribed}) , noun

[Latin amiantus, Greek {not transcribed} (lit., unsoiled stone) a greenish stone, like asbestus; 'a priv. + {not transcribed} to stain, to defile; so called from its incombustibility.]

(Mineralogy) Earth flax, or mountain flax; a soft silky variety of asbestus.