What do you mean by the term reformation?

Hint :Some Protestants, such as Landmark Baptists, prefer to ascribe the commencement of the Reformation to reformers such as Arnold of Brescia, Peter Waldo, John Wycliffe, Jan Hus, Petr Chelick, and Girolamo Savonarola, in the tradition of the Radical Reformation. Utraquist Hussitism was recognised by the Council of Basel and was officially tolerated in the Crown of Bohemia, thanks to the reform efforts of Hus and other Bohemian reformers, though other movements, such as the Lollards in England and the Waldensians in France and Italian regions, were still persecuted.

Complete Step By Step Answer:
The Protestant Reformation (also known as the European Reformation) was a religious and political movement in 16th-century Europe that posed a religious and political challenge to the Catholic Church, particularly papal authority, arising from what were perceived to be errors, abuses, and discrepancies by the Catholic Church. The Protestant Reformation marked the beginning of Protestantism and the division of the Western Church into Protestantism and the Roman Catholic Church. It is also regarded as one of the events that marked the end of the Middle Ages and the start of Europe's Early Modern Era.
Many other reform movements existed before Martin Luther. Although the Protestant Reformation is often seen to have begun with Martin Luther's publishing of the Ninety-five Theses in 1517, there was no rupture between the Catholic Church and the embryonic Luther until the Edict of Worms in 1521. The edict denounced Luther and forbade Holy Roman Empire people from defending or disseminating his beliefs. The fast transmission of religious literature in the vernacular was made possible by the development of Gutenberg's printing press. Because of the protection of Elector Frederick the Wise, Luther was able to survive despite being labelled an outlaw.

Note :
Other reformers, such as Huldrych Zwingli and John Calvin, sprang from the first movement in Germany. Diet of Worms (1529), establishment of the Lutheran Duchy of Prussia (1525), English Reformation (1529 onwards), Council of Trent (1545–63), Peace of Augsburg (1555), excommunication of Elizabeth I (1570), Edict of Nantes (1598), and Peace of Westphalia are some of the major events of the time (1648). The Catholic Reformation, also known as the Catholic Revival or the Catholic Counter-Reformation, was a period of Catholic reforms undertaken in reaction to the Protestant Reformation. The date of the Reformation's termination is debatable.