McAree is King, M'Adarragh is Oak, M'Lave is Hand, M'Shane is Johnston or Johnson, M'Gowan is Smith, M'Caffrey is Beatty etc etc.Now, unless you understand the Irish language there is no way you could work those names out.There are literally hundreds of names which are derived from the old Irish words. Many names describe the trade of the person or their appearance. Bawn indicates "white" while Roe indicates "red" and Mor indicates "big".This same rule applies to the Townland system where "Clon" indicates flat land and "Drum" indicates hilly land.Griffiths Valuation uses a similar system to differentiate between members of the same family name.Sometimes the trade name - e.g. Cooper is added to the surname to make it clear that he was a "cooper". Corruption also occurs regularly where an English name is involved - Whiteacre became Whittaker, French names dating back to the Norman period still exist - Lammy derived from L'Ami the French word for friend.In County Monaghan the common name "Quigley" is interchangeable with Cogley, Kegley and in Belfast area - Twigley.The name Nielson which appears in the Donagh area of Monaghan became Nelson and the Ulster name "Lennon" is derived from Lannan & Linnen. My experiences of names dates back to my days as a Teacher of the Irish language where we often referred to the "O'Neills" as "Nails" and to the "Wallaces" as "Wallis" For a list of all the changes which names have been subjected to - e-mail me directly on firstname.lastname@example.org & I will send you the full data.