At one time, first and second names had sensible meanings. Thomas meant a twin, Alice meant truth, William meant strong minded and most likely our remote ancestors had to earn their names. But nowadays parents tend to name their children. for older relatives. An only child might be named Thomas after an uncle who was a twin and young William might be a sissy.
The original meanings of first names were forgotten long before second names were invented. At first second names also made sense, but they also soon lost their meanings, In England, second names came into style about 900 years ago. William the Conquerer was completing the Doomsday Book, a list of his subjects and their properties.
There were long lists of Johns.: and Sams, Toms and Bills and no way to tell which Tom was which or one Bill from another. So a bit of extra information was added to each name. There was Thomas the Baker and Thomas the Butcher, William the Carpenter and William
Baker the Miller. This good idea soon became Tom/and Bill Miller and second names came into style.
The second name was applied to the whole family and Tom Bakers wife and children were also Bakers. The family name was handed on, and Tom Baker’s son kept the name Baker, even if he became a Vut olvar or a carpenter.
In Ireland and Scotland, the second name was often taken from the father’s first name, O‘Brian means son of Brian and MacDonald means son of Donald. Some families were named for places. The Hills and Wells, the Lakes and Woods originally may have been named for the places where they lived. Some families took their names from inns and taverns. Old inns were often named for animals, famous persons or outstanding objects. The family names Lamb and Lyon, Wolf and Swann, King and Queen may date back to ancestors who named themselves after their favorite inns.
Nowadays it is odd to find a man named Tailor who makes suits or a man named Baker who runs a bakery. But when second names were first invented, most of them made sense. However, they have long since lost their meanings and in some cases it is almost impossible to trace back the original meanings of our family names.