in par·ti·bus in·fi·de·li·um \(ˌ)inˈpärd.əbəˌsinfəˈdālēəm\adverb alsoin partibus Etymology: Medieval Latin, literally, in the regions of infidels : in ideologically hostile or unsympathetic surroundings < made himself missionary in partibus infidelium for American philosophic naturalism — J.H.Randall >