In Scotland and northern England a Linn is a geographical water feature.
In Scotland it describes where a watercourse has cut through a shelf of hard rock creating a narrow (usually), steep-sided cut though which the watercourse runs.
Typically there is only one named Linn on any watercourse - although obviously - there may actually be more than one feature with the necessary attributes.
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:
A couple of miles below Faindouran Lodge the A'an is spanned by a bridge. Here the river is narrow, with foaming rapids and deep pools where salmon lie of a September day. Beside the Linn, on the damp granite ledges ...— Gordon (1925) (p61)
At the Linn beside Inchrory the A'an thundered through its rocky gorge. Before midsummer salmon and grilse reach the deep pools of the Linn ...— Gordon (1925) (p62-63)
- Gordon, Seton (1925). The Cairngorm Hills Of Scotland. London, England.: Cassell and Company.
Gazetteer for Scotland "Glossary:L". Retrieved 2 January 2008. England's Rock Art - Roughting Linn, Northumberland