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David Speers of Causeway Books recognised the place-name as Lagadrade and Pat McKay of the Northern Ireland Place-Name Project at Queens University Belfast provided the following derivation:
It seems that Irish Log an Droichid 'hollow of the bridge/crossing place' is the most satisfactory interpretation as suggested by the local pronunciation and that 'Logenadoaid' is a corruption. Info on pronunciation of 'Cowenfishyn' as 'Carnfishin' is also interesting. I'm sure the first element is Irish 'carn' but the final element is obscure.
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Carnfishin is in the townland of Ballyhemlin and Lagadrade might overlap the townlands of Magheraboy and Ballaghmore.