a method of dyeing
繧 centers on a specific dyeing technique, referring to a method of applying color to fabric. The meaning is narrow and technical, without broader abstract extensions.
繧 combines 糸 (thread, textile) with 雲 (cloud), likely as a phono-semantic compound where 雲 contributes the sound ウン and the textile radical points to a dyeing method. The exact historical development is uncertain.
The left side 糸 is thread or cloth, and the right side 雲 is a cloud. Imagine dyeing fabric by dipping it into a cloud of colored mist, leaving a soft, even pattern.
For ウン, picture a woolen cloth being dyed: the 'wool' in woolen sounds like ウン, and the cloth soaks up the dye.
—
ungen; method of dyeing in which a color repeatedly goes from dense to diffuse, diffuse to dense; used in Buddhist pictures, temple ornaments, etc., during the Nara and Heian periods