SYNOD. - It is the legitimate assembly, convened by the bishop, of the priests and clerics of his diocese and of others who are obliged to attend, for the purpose of discussing and deliberating on matters concerning the pastoral care. The particular task of study of the synod are the pontifical constitutions, the prescriptions of the Roman Congregations, the Statutes of predecessor bishops and furthermore «constituere quae ad vitia coercenda, virtutem promovendam, depravatos populi mores reformandos et ecclesiarum disciplinam aut restituendam aut fovendam necessaria et utilia esse iudicaverit».
On the basis of the definition formulated above, and compiled by Benedict XIV in De Synodo diocesana, the synod must always be considered a diocesan convocation, unlike the Council which, whether ecumenical or particular, is an assembly of all the bishops of the Catholic world or, in the case of a regional or provincial Council, the gathering of several bishops. The fundamentally important difference between the Council and the synod lies in the power, which is legislative in the conciliar assembly, whereas in the synod it is simply consultative, inasmuch as the sole legislator is the bishop, to whom belongs the right of subscribing the constitutions, to the exclusion of collective suffrage (can. 362 CIC). On the basis of this principle, the legitimacy of the synod is subject to the personal presence of the bishop or of the vicar general, who has received a special mandate from the bishop. It is also obvious that the capitular vicar has no power to convoke the synod.
Synodal assemblies have a remote origin in the church: it appears that the first was convoked by Pope Siricius in Rome in 387; originally, however, they differed from councils only in their purpose, since these are terms which, taken etymologically, are synonyms. The Fourth Lateran Council of 1215 laid down the first precise norms, suitable for preventing any possibility of confusion with Councils. Subsequently the Council of Trent greatly increased the importance of the synod, imposing on bishops the obligation of celebrating it annually (sess. XXIV, De ref., cap. 2). Only in the 17th century did synodal meetings suffer a setback, because of the accusation of Jansenism that the Synod of Pistoia of 1786, convoked by bishop Scipione de' Ricci (v.), received from the pontiff Pius VI with the constitution Auctorem fidei of 1794.
The CIC has moderated the norms sanctioned by the Council of Trent, extending to a decade the obligation of convoking the synod, and this, as has been observed by some authors, because the canon law in force, being more perfect, provides more concretely for the spiritual needs of the clergy and of the faithful. On the basis of can. 356 § 2, if the bishop governs several dioceses aequae principaliter, the convocation of a single synod is sufficient, and it must always be celebrated in the Cathedral Church, nisi aliud rationalis causa suadeat (can. 357 § 2). Those obliged to attend the synod, unless they are detained by a legitimate impediment, are the vicar general, the canons of the Cathedral Church and the diocesan consultors, the rector of the diocesan seminary saltem maioris, the vicars forane, one member of the collegiate churches, elected by the Chapter, the parish priests of the city where the synod is celebrated, at least one parish priest from each forania, the abbots de regimine, one of the superiors of each clerical religious order residing in the diocese designated by the provincial. It is instead left to the discretion of the Ordinary to convoke the canons, parish priests, religious superiors and other priests of the diocese, excluding however those needed for the care of souls. The Ordinary may apply penalties with regard to those who are obliged to attend (can. 359 § 2) and who in fact do not appear without having made the bishop aware of the reasons that compelled them not to participate. Before the sessions of the synod the bishop convokes the commissions and the participants are offered a draft of the constitutions that form the object of discussion (can. 360 §§ 1-2).
The name of synod is also used in the Waldensian Church, in which it is an annual legislative assembly, composed of ministers and laymen, with deliberative or merely consultative vote.