What does "crottle" mean?

Any of various lichens gathered for dyeing, especially those of the genus Parmelia.

What is a synonym for "crottle"?

Common synonyms include: brushwood, bulge, choke, compress, constrict, control.

noun

noun ·Rare ·Advanced level

Noun

1
Any of various lichens gathered for dyeing, especially those of the genus Parmelia.
"It was known and uſed as a dye-ſtuff in the Highlands of Scotland by the name of corkes or crottel, ſome hundred years ago."
2
any of several lichens of the genus Parmelia from which reddish brown or purple dyes are made wordnet

"It was known and uſed as a dye-ſtuff in the Highlands of Scotland by the name of corkes or crottel, ſome hundred years ago."

From Scots crottle, from Scottish Gaelic crotal.