Around the corner at Language Log Victor Mair quotes from a recent paper, E.J.W. Barber, "Of Salt Men and Cloth: The Remarkable Textile History Preserved in Eurasian Salt-beds," Sino-Platonic Papers, No. 345, My 2024.
Sinologists have long wondered why the words for “blue” and “cabbage” in Chinese are homonyms: both 藍 lán in Mandarin. But just recently, perusing dye information about woad [VHM: a common plant dye for blue] from Richard Laursen, Victor Mair noticed that woad is actually in the cabbage family, Brassicaceae (earlier called Cruciferae), and that rural people have long found ways to get blue coloring out of a number of types of cabbage (Mair 11/22/2023), especially the purple kind. Hence the unexpected homonyms. Thus, from all these textiles preserved in salt, we even have the solution of an interesting etymological conundrum.