Word of the Day


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Liz Potter
Written by Liz Potter


a common lichen found on rocks

View the full definition in the Macmillan Dictionary.

Origin and usage

The noun crottle is used mainly in Scotland. It comes from the Gaelic ‘crotal, crotan’ meaning a lichen. It was first used in English in the late 18th century.


One of the joys of the Open Dictionary is the entries for things that are completely unfamiliar, often submitted by specialists. One recent example is crottle, also spelled crotal, the name used in Scotland for a type of lichen that usually grows on rocks though it sometimes grows on trees and bark. The Latin name for crottle is Parmelia saxatilis and it is, I learned, a blue-grey or green-grey lichen that is used to make dyes that, slightly surprisingly, are not bluish, greenish or greyish: they are, in fact, deep red browns and rusty oranges, and are used to dye cloth including the famous Harris tweed. Lichens are the result of a symbiotic partnership between fungi and algae but have different properties from either. They have no roots, but they do photosynthesize like other plants. The entry for crottle was submitted by a user called Samantha, who may or may not be an expert on lichens, or plant dyes. Whether you are an expert or not, your contributions to the Open Dictionary are very welcome. You can submit them here.


“The crottle is put into the bath with a sufficient quantity of water, boiled up, allowed to cool, then boiled up with the wool until the shade required is got.”
(enTenTen15 corpus)

“Hummingbirds use crottle lichens to camouflage their tiny nests, fastening it to the outside using strands of spider web.”
(enTenTen15 corpus)

Related words

algae, fungus, lichen, moss

Browse related words in the Macmillan Thesaurus.

About the author

Liz Potter

Liz Potter

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