The theological system of any of the churches of western Christendom that separated from the Roman Catholic Church during the Reformation WordNet 3.0 & Open English WordNet

Protestantism is a branch of Christianity that follows the theological tenets of the Protestant Reformation, a movement that began in the 16th century with the goal of reforming the Catholic Church from perceived errors, abuses, and discrepancies. Wikipedia

The second largest form of Christianity Wikipedia Disambiguation

Division within Christianity, originating from the Reformation in the 16th century against the Roman Catholic Church, that rejects the Roman Catholic doctrines of papal supremacy and sacraments Wikidata

The forms of Christian faith and practice that originated with the doctrines of the Reformation. OmegaWiki

The Protestant (rather than the Roman Catholic or Orthodox) Christian faith. Wiktionary

Faith. Wiktionary (translation)