*byssu*

‖n.; pl. E. Byssuses L. Byssi. ety>[ L. byssus fine flax, fine linen or cotton, Gr. by`ssos . ] [ 1913 Webster ]

1. A cloth of exceedingly fine texture, used by the ancients. It is disputed whether it was of cotton, linen, or silk. [ Written also byss and byssin. ] [ 1913 Webster ]

2. (Zool.) A tuft of long, tough filaments which are formed in a groove of the foot, and issue from between the valves of certain bivalve mollusks, as the Pinna and Mytilus, by which they attach themselves to rocks, etc. [ 1913 Webster ]

3. (Bot.) An obsolete name for certain fungi composed of slender threads. [ 1913 Webster ]

4. Asbestus. [ 1913 Webster ]