In Scotland and northern England, 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 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,[1] with the derivation a confusion of Scots Gaelic linne (pool) and Old English English, Old (ca.450-1100);: hlynn (torrent).[1]
Gazetteer for Scotland "Glossary:L". Retrieved 2 January 2008.England's Rock Art - Roughting Linn, Northumberland
Notes: