Perhaps from southern French Mistre, a variant of Maitre, from Middle French maistre (“master”).
Meanings
A surname.
I researching Daniel Mixter who was born in the Town of Prescott, Ontario, Canada on July 5, 1809. 1996 April 27, KdCaLeLaMg, “MIXTER Daniel; CAN; b. 1809”, in soc.genealogy.surnames (Usenet):