The act of reforming, or the state of being reformed; change from worse to better; correction or amendment of life, manners, or of anything vicious or corrupt; as, the reformation of manners; reformation of the age; reformation of abuses.
Specifically (Eccl. Hist.), the important religious movement commenced by Luther early in the sixteenth century, which resulted in the formation of the various Protestant churches.
Division in the Western church beginning early in the sixteenth century and leading to the foundation of Protestantism. Although the medieval church had come under attack for corruption, the revolt fomented primarily by Luther and Calvin was theological in focus, criticizing Roman Catholic doctrine on redemption and grace. It emphasized the principles of sola fide and sola scriptura.