According to the International Genealogical Index, this surname is recorded in the spellings of Clitston, Clitstone and Clatson. It would seem to be English and despite the third spelling, locational either from a place such as Clipston or Clipstone, found in various counties of East Anglia, or possibly from some now 'lost' medieval village, of which the only surviving memory in the late 20th century, is the surname itself. Assuming that Clitsome is the original spelling the origin would seem to be from a place called 'the house on the cliff,' from the Olde English pre 7th century 'cleof - husum', however this is conecture. What we do know is that as a locational surname it was originally a 'from' name. That is to say a name that was given to a person after he or she left their original homes to move somewhere else. The easiest way to identify such 'strangers' was to call them by the name of the place from whence they came. The surviving church registers of the diocese of Greater London include some interesting examples such as June Clatson who married Mathew Hamon at St Dunstans in the East, Stepney, on April 27th 1627, and about a century later that of Elizabeth Clitsome who married Frances Benard, at the same church, on June 5th 1729.