Obviously, no one knows for certain. However, the English branch of the family originally had the surname "Southmeade", also variously spelled Southmead, Southmed, and Southmede. It is believed that the surname Southmeade came, as many such names did, from a description of the location at which the original family resided.

A "meade" or "mead" in medieval England was a piece of low-lying land that was often wet in the winter season. This is now called a meadow. The conjecture by Southmayd family historians is that our original family members lived on the south end of a meadow, probably in Devon County, England, and were variously known as the people on the south end of the meade, or those crazy people on the south meade, and eventually the Southmeade's.

When William Southmeade came from Devon to Gloucester, Massachusetts circa 1640, he initially utilized the Southmeade surname. But, at the time of his marriage to Millicent Addis in 1642, he changed the spelling to Southmayd, and continued to use that spelling throughout his life. William's son, William Southmayd, continued to use the spelling and it has stuck since that time.

The last of the Southmeade's in Devon died out in 1839. However, the Southmayd's in America, so surnamed by William Southmeade the colonist from Devon, have continued to flourish.