TARN (O. Eng. tame, Scand. Ijarn, tjiirn, tjorn, etc.), a name applied in England (especially in the Lake District) and in Scotland to small lakes or pools in mountainous districts, especially to such as have no visible affluent streams. The term is sometimes used also of a marsh or bog.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)