Persian origin
The name Tamzin is derived from the Old Persian word "tamzaran", which means "daughter of the sea" or "wave-born".
In Persian mythology, Tammuzian or Tammuz was a deity of fertility and agriculture.
Cornish origin
The Cornish variant is derived from the Old Cornish name "Tamsyn", which is a diminutive form of the name Thomas, meaning "twin".