The correct term for an Indian prince or ruler is rajah. It may also be spelled raja and is short for rajkumar.
The word rajah originates from the Hindi word rājā. That word in turn is derived from the Sanskrit word rājan, which means king. The first recorded use of rajah was around the year 1555.
A rajah can be an Indian prince, king or chief. The word can also describe the bearer of a noble title instead of being a title itself. It is a traditional inherited designation in Hindi culture.
Princess is the term for a Hindi female ruler.