This is a very interesting and complex medieval surname, with over one hundred spellings in different languages. It derives from the pre 7th century Frankish (French) personal name 'Theodore,' itself a derivative of the famous ancient Greek 'Theodoricus', translating as 'Gods gift'. This meaning no doubt spurred its popularity in almost every European country. Examples of the surname recordings in France from the 17th century include Thierry, Thery, Thiriet, Thiriot, Thyriet etc. In England its most popular form was (and is) as Terry, in Wales Tudor (the ancient surname of the king's of Wales), in Italy Todari, and in Russia Fedunov. In Canda and the USA there seems to be some confusion as to the meaning and origin, with a claim that it is of Acadian origins and a variant spelling of Thierry. Acadia, the original French part of Canada, is now New Foundland, the original French Acadians being forced out by the British (although this was later partly rescinded and many went back) and they settled mainly in the New England states of America, with a about eighty travelling as far south as Louisiana, (New Orleans) then a French state. As far as we know settlers called Theriot have always had that surname since records began, although sadly few in France survived the revolution of 1792 when nearly all ancient records were destroyed on the orders of the Revolutionary Government. It is also true that crossing the Atlantic anytime between 1720 and 1910 particularly to New York - might well lead to a name change, but this does not apply here. Amongst the early surviving surname records in France are those of Catharine Theriot who married Jean Dogne on November 2nd 1681 at Rosieres aux Saline, Meurthe-et-Moselle, whilst Anne Gertrude Theriot married Felix Boudroux at Morlais St Martin, Finistere, in 1764, the actual date not being recorded.