History does some unusual things to names but rarely more so than this dialectually transposed spelling. The origination is from the ancient Hebrew John to the Anglo - Saxon Johan and hence to the medieval female name Janet or Jennet, which are themselves diminutives translating as 'the son (et) of Jan'. In 1307 the recording of Willelmus filius Jonet is found in the Pipe Rolls of Wakefield, Yorkshire whilst John Ionet, was recorded in the accounts of the Duchy of Cornwall circa 1300. The recordings as 'Joynt' appear to be of London origins as shown below whilst William Joint married Louisa Mogridge on May 6th 1867 at St. Pancras Old Church, London. The first recorded spelling of the family name is shown to be that of Edward Joynt, which was dated July 2nd 1691, married Thomas Knight at St. Katherine by the Tower, London, during the reign of King William III of Orange and England, 1689 - 1702. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.