 The oldest version of the modern name Shetland is <unk> recorded in 1190 becoming Hetland in 1431 after various intermediate transformations . This then became Hjaltland in the 16th century . As Shetlandic Norn was gradually replaced by Scots Hjaltland became <unk> . When use of the letter yogh was discontinued , it was often replaced by the similar @-@ looking letter z , hence Zetland , the mispronounced form used to describe the pre @-@ 1975 county council . However the earlier name is Innse Chat – the island of the cats ( or the cat tribe ) as referred to in early Irish literature and it is just possible that this forms part of the Norse name . The Cat tribe also occupied parts of the northern Scottish mainland – hence the name of Caithness via the Norse <unk> ( " headland of the cat " ) , and the Gaelic name for Sutherland , Cataibh , meaning " among the Cats " . 
