Coba lihat mbah wiki:

[1] http://en.wikipedia.org/wiki/Protestantism

The exact origin of the term protestant is unsure, and may come either from French: protestant or German: protestant. However, it is certain that both languages derived their word from the Latin: protestantem, meaning "one who publicly declares/protests",[2] which refers to the letter of protestation by Lutheran princes against the decision of the Diet of Speyer in 1529, which reaffirmed the edict of the Diet of Worms in 1521, banning Martin Luther's 95 theses of protest against some beliefs and practices of the early 16th century Catholic Church.[1]

Lagi kalo Protestan berasal dari pro-teis, lha Katolik apa gak pro-teis juga? Maksa lu Lan...