In Scotland and northern England (Northumberland, Cumbria and Durham), a Linn is a geographical water feature, a watercourse that has cut through a shelf of hard rock creating a narrow (usually), steep-sided crevice (fracture) through which it runs, typically in the form of a waterfall.
Typically one named after a river or area can have application even for more than one such feature.
The photograph of the Linn of Dee illustrates the attributes of a typical 'Linn'.
In Gordon (1925) the author describing a walk down Glen Avon in the Cairngorms mentions two Linns on the River Avon - first:
Second:
A linn may also refer to a waterfall or a pool at the foot of a waterfall, with the derivation a confusion of Scots Gaelic linne (pool) and Old English (torrent).
Gazetteer for Scotland "Glossary:L". Retrieved 2 January 2008. England's Rock Art - Roughting Linn, Northumberland
Notes: