Ar feadh an lae = for the duration of the day. ar feadh an lae go léir = during the whole day, all day long. D'fhan sé i n-a shuidhe sa chathaoir ar feadh an lae go léir. = he remained sitting in the chair all the day long.
fanfad annso ar feadh mo shaoghail = for the duration of my life. Bhíodar ag obair ar feadh an lae go léir gan biadh. = They were working the whole day (duration) without food. Níor chodail sé néal ar feadh trí lá agus trí oidhche.