What is the definition of "protestant"?

The word "protestant" is either a noun or an adjective and at its simplest refers to the act of protesting or a person who protests. As a proper noun, the word "Protestant" refers to any Christian who does not adhere to Eastern Orthodox, Catholic or Anglican doctrines.

Protestant Christians can also be defined as members of any Christian church that was established during the Reformation as a separate entity from the Roman Catholic church. Originally, the term "Protestant" referred to a group of princes in Germany who rose up in protest in 1529 against the Diet of Speyer who denounced the Reformation.