Protestant

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A member of a Western Christian church whose faith and practice are founded on the principles of the Reformation, especially in the acceptance of the Bible as the sole source of revelation, in justification by faith alone, and in the universal priesthood of all the believers.
2. n. A member of a Western Christian church adhering to the theologies of Luther, Calvin, or Zwingli.
3. n. One of the German princes and cities that supported the doctrines of Luther and protested against the decision of the second Diet of Speyer (1529) to enforce the Edict of Worms (1521) and deny toleration to Lutherans.
4. n. One who makes a declaration or avowal.
5. adj. Of or relating to Protestants or Protestantism.

Century Dictionary and Cyclopedia

1. Protesting; making a protest.
2. [capitalized] Of or pertaining to Protestants or their doctrines or forms of religion.
3. n. One who protests; one who makes protestation.
4. n. [capitalized] A member or an adherent of one of those Christian bodies which are descended from the Reformation of the sixteenth century: in general language, opposed to Roman Catholic and Greek. The name, first applied to the Lutherans who protested at the Diet of Spires in 1529, came to be applied to Lutherans generally, and afterward was extended to Calvinists and other opponents of the papacy in countries where the papacy had formerly been in power. (See protest of Spires, under protest.) The Protestants gained a strong foothold in some countries, as France, in which they are now numerically weak. They are in the majority in Great Britain and many of its possessions, in Germany, the Netherlands, Switzerland, the Scandinavian countries, and the United States.

Wiktionary

1. n. Christianity Any of several denominations of Christianity that separated from the Roman Catholic Church based on theological or political differences during the Reformation.
2. n. Christianity Someone who is a member of such a denomination.
3. n. Christianity A modern Christian denomination not belonging to the Catholic or Orthodox traditions.

GNU Webster's 1913

1. n. One who protests; -- originally applied to those who adhered to Luther, and protested against, or made a solemn declaration of dissent from, a decree of the Emperor Charles V. and the Diet of Spires, in 1529, against the Reformers, and appealed to a general council; -- now used in a popular sense to designate any Christian who does not belong to the Roman Catholic or the Greek Church.
2. adj. Making a protest; protesting.
3. adj. Of or pertaining to the faith and practice of those Christians who reject the authority of the Roman Catholic Church.

WordNet 3.0

1. n. an adherent of Protestantism
2. n. the Protestant churches and denominations collectively
3. adj. of or relating to Protestants or Protestantism
4. adj. protesting.