Wikipedia
Mistri, or Mistry, is a term for a master-craftsman, or supervisor of manual workers in India. However, Mistri is nowadays being replaced with "supervisor" and other terms, as with the Indian Railway who replaced it with supervisor in 2005.
The term was adopted into Gujarati from the Portuguese mestre, meaning "master" or "teacher". The Kshatriyas worked on building Dui Fort – which became the city of Diu, in which the Portuguese were present from its foundation in 1535 until 1961 – and the Portuguese called them mestre due to their skills at fort building.
In Suthar culture, mistri also meant contractor – mainly for the Mistris of Kutch, the majority of whom worked as railway, PWD and forest contractors during British rule. Many Parsi families working as contractors therefore also adopted the surname Mistry as their occupational surname, as in the example of Pallonji Mistry.