The Collaborative International Dictionary of English v.0.48:
Lough \Lough\, n. [See 1st Loch.] A loch or lake; -- so spelt in Ireland. [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Lough \Lough\, obs. strong imp. of Laugh. --Chaucer. [1913 Webster]WordNet (r) 3.0 (2006):
lough n 1: a long narrow (nearly landlocked) cove in Ireland 2: Irish word for a lake