Protestant, adj. and n. A believer who is not Catholic or Orthodox.
Unlike the other two, Protestants do not have a continuous line from
the beginning. Rather, they broke off (sometimes voluntarily,
sometimes involuntarily) from the Catholic Church, believing that the
adherence to Tradition was inappropriately obscuring Scriptural
teaching, such as James's doctrine of salvation by faith and faith
alone. They held to the doctrine of Sola Scriptura, meaning that they
would not take Tradition as a basis for doctrine, but instead only use
the Scriptures which supported their views. Today, still holding
strongly to Sola Scriptura and other important traditions, they have
seminaries (attendance to which is requisite to clerical positions)
which teach the faith from extensive creeds and confessions, designed
to remove the confusing task of directly interpreting the Scriptures.
- -- Hayward's Unabridged Dictionary