The Tönsing Surname is an example of a patronymic surname, derived from Antonsen. It is related to the names Antonsen, Tönnessen, Tönnies and similar names. The name occurs most often in the area of Germany between Melle, Osnabrück, Münster and Bielefeld.
A freehold estate of the family Tönsing is recorded in Wimmer, near Melle, around 1500. In Schloemann: Besiedlung und Bevölkerung der Angelbecker Mark, the name Tönsing is used as an example of an estate that derived its name from a family (Antonius), and which gave the current owner its name. This estate had the name since 1500. (p. 283) The implication is that the Tönsing-hof was a freehold estate since then.
Emigrants from Germany took the name with them to the USA, South Africa and Australia, wher the name was changed variously to Toensing, Tonsing, or Tonzing.
An unrelated occurence of the name Tonsing is in Burma and Northeastern India, where the root is most probably related to the local language there.