Archaic, jocular term for the color purple or violet. Cross-referenced with 紫 (むらさき). Not used in modern standard Japanese.
See also: 紫
In old waka poetry, 此の糸 can be written to mean the color purple.
The derivation is uncertain; the kanji literally mean 'this thread', possibly a playful or poetic reference to purple dye or thread in classical contexts.