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.
To reform a world, to reform a nation, no wise man will undertake; and all but foolish men know, that the only solid, though a far slower reformation, is what each begins and perfects on himself. Thomas Carlyle
The story of Christian reformation, revival, and renaissance underscores that the darkest hour is often just before the dawn, so we should always be people of hope and prayer, not gloom and defeatism. God the Holy Spirit can turn the situation around in five minutes. Os Guinness
The Protestant Reformation had a lot to do with the printing press, where Martin Luther's theses were reproduced about 250,000 times, and so you had widespread dissemination of ideas that hadn't circulated in the mainstream before. Nate Silver