This fairly obscure term is sometimes used in Spain as a synonym for procurador/a, being defined in the DLE as procurador o representante de una parte en el proceso. As examples, se dio traslado al causídico… simply means that “the procurador was notified” about the matter in question. Apoderamiento del causídico denotes “power of attorney granted to the procurador, while designación de causídico mediante comparencia ante el Secretario Judicial is a reference to a client’s appointment (i.e., grant of power of attorney) to his procurador in person in the presence of a court clerk (known formally as designación apud acta), rather than by submitting a poder notarial (“notarial power of attorney”).