crottle vs crotal

crottle and crotal both are nouns.

Word	Noun	Adjective	Verb	Adverb
crottle	Yes	No	No	No
crotal	Yes	No	No	No

As nouns, crottle and crotal are synonyms defined as:

crottle and crotal: any of several lichens of the genus Parmelia from which reddish brown or purple dyes are made

Other synonyms of crottle include crottal.

crottle (noun)	crotal (noun)
any of several lichens of the genus Parmelia from which reddish brown or purple dyes are made	any of several lichens of the genus Parmelia from which reddish brown or purple dyes are made