This is an anglicized form of an Olde Gaelic (Scots and Irish) personal/nickname 'cinneidigh or cinneide', a compound of the elements 'cinn' meaning 'head', plus 'eide' translating variously as 'grim' or 'helmeted'. Cinneide was the nephew of Brian Boru, High King of Ireland (1002 - 1014), and the surname O Cinneide (the Gaelic prefix 'O' indicating 'male descendant of') came into being in Ireland in the 11th Century. The 'Annals of the Four Masters' record an O Cinneide, Lord of Tipperary in 1159. The first recorded Scottish name bearer appears to be Gilbert Mac Kenedi who witnessed a charter in Melrose circa 1165 - 1170. (The prefix 'mac' means 'son of'). The Scottish Kennedys are by remote origin Irish Gaels. In 1296 one, Alexander Kennedy was canon of Glasgow. Duncan Kennedy, provost of Aberdeen, 1321 - 1322 was the first recorded of the name in the north east. The Kennedy's held the lands of Kermuck (Aberdeenshire) for generations. The first recorded spelling of the family name is shown to be that of Henry Kennedy or Mac Kenede, which was dated 1185 - Leader of a rebellion in Galloway, during the reign of King William, The Lion of Scotland, 1165 - 1214. 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.