the green of An Fhinn
An Fhinn – River Finn

This name might be expected to contain the definite article: Faiche na Finne as is the case in nearby Caisleán na Finne (Castlefin). There is no trace of the article in the historical forms of the name, however, and it is evident that the article was not always used in the name of the river. In Beatha Aodha Ruaidh, references to the name appear both with and without the article: ‘tar Bearnas Mór, tar Finn, tar Modhairn’ (1593, p 48); ‘dar Finn hi cenél Eoghain mic Néill’ (1601, p 272); ‘for ur na Finne alla thiar’ (1600, p 262).

All that being said, the noun finne (“fairness (of hue, complexion), brightness”, DIL; “whiteness, fairness”, FGB) must also be considered as a possible precursor to the second element of this name: Faiche Finne “the green of whiteness, fairness”.