byssus

UK: /ˈbɪsəs/ US: (bis′əs)

WordReference Random House Unabridged Dictionary of American English © 2025

bys•sus  (bis′əs), n., pl. bys•sus•es, bys•si 

(bis′ī). 
1. Zoology a collection of silky filaments by which certain mollusks attach themselves to rocks.
2. an ancient cloth, thought to be of linen, cotton, or silk.

• Semitic; compare Hebrew būts
• Greek býssos a fine cotton or linen
• Latin
• 1350–1400; Middle English

bys•sa•ceous  (bi sā′shəs), bys′soid, adj.  bys′sal, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

byssus / ˈbɪsəs/ noun (byssuses, byssi / ˈbɪsaɪ/)

1. a mass of strong threads secreted by a sea mussel or similar mollusc that attaches the animal to a hard fixed surface

Etymology: 17th Century: from Latin, from Greek bussos linen, flax, ultimately of Egyptian origin