||Bys"sus (&?;), n.; pl. E.
Byssuses (&?;); L. Byssi. (&?;) [L.
byssus fine flax, fine linen or cotton, Gr. by`ssos
.]
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.]
2. (Zoöl.) 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.
3. (Bot.) An obsolete name for certain fungi
composed of slender threads.
4. Asbestus.