Fathom Fathom A fathom is a unit of length in the imperial and the U.S. customary systems equal to , used especially for measuring the depth of water. There are two yards (6 feet) in an imperial fathom. Originally the span of a man's outstretched arms, the size of a fathom has varied slightly depending on whether it was defined as a thousandth of an (Admiralty) nautical mile or as a multiple of the imperial yard. Formerly, the term was used for any of several units of length varying around . The name derives from the Old English word "fæðm", cognate
Fathom Castle Fathom Castle Fathom Castle, also known as Feedom Castle, was a castle in Fathom (sometimes 'Fidun') County Armagh near Newry, County Down, Northern Ireland. A stronghold of the O'Neill's, the castle was taken by the English during the Nine Years War and was then demolished in 1730 for the development of a canal. Originally it was a holding of Hugh DeLacy, as there is reference to an 'old castle' being there, before Shane O'Neill built his structure c. 1550's and used it as a primary residence. Being on the western approach to the settlement at Carlingford, where King John's Castle