Thompson : English and Scottish Patronymic name from Thomas (twin) which was a popular name in the Middle Ages (and still is...). The name Thomas comes from an Aramaic term for "twin." It was one of the really popular given names at a very early time, which led to people who bore the name achieving some renown, leading to an increased popularity. The first letter of the name was originally the Greek "theta" which accounts for the TH spelling -- the pronunciation of which was lost due to the French influence in the earliest stages of the name. As with many of the early popular given names, they became the subject of variations due to familiarity or fondness -- pet names, if you will -- in the same fashion that William Clinton is called Bill, or William Mayes was called Willie. Several of the pet forms of Thomas (there are loads of them, like Tom, Tommy, etc.) did not carry on as given names to modern times, and involved the letter -p, which was generally added as a pronunciation aid to make a pet form. For example, from Thomas came the pet form Thompkin, similar to Thumbkin being a "little thumb" (a nursery rhyme). Thompkin was "little Tom" and when someone described his son, they might say William -- Thompkin's son. They also contracted names or dropped the diminutive (or pet) form, which would cause Thompkin as an adult to be known as Thom or Thomp, for short. His son might be described as William -- Thomp's son. And that is what Thompson means -- son of the man known as Thom, Thomp, or Thompkin, or other diminutive form of Thomas.


Source:  Broken Arrow Publishing