This is a very rare English surname. It is almost certainly locational and is today, or at least has been in the past , recorded in several forms including Boyack, Boyock, Bayock and Bayott. As to which is the correct or original form, the answer would seem to be 'none of them!' The very vagueness of the spelling clearly suggests a 'lost' place name. Some five thousand surnames of the British Isles are believed to derive from the names of now 'lost' villages. The only public reminder in the 20th century of the existence of these places is the surname, often as with this name in a myriad number of spellings. Locational surnames are in any case 'from' names. That is to say that they were originally given either to the local lord of the manor and his family, or to people who left their original homes, and for whatever reason moved elsewhere. Spelling being at best erratic and local dialects, even between adjoining villages, very 'thick', often lead to the development of 'sounds like' surnames. There are several places in England with a spelling commencing 'Boy' and all refer to an Olde English tribal name 'Boia' of the pre 7th century, plus an ending which is usually 'ton' meaning farm, or 'thorp', an outlying settlement. The earliest example of the surname that we have been able to find is that of Thomas Boyack, whose daughter Mary, was christened at the famous church of St. Georges in the East, city of London, on September 12th 1732.