VATICAN CITY (CNS) -- The word "synod" derives from the Greek word "synodos," meaning "to walk together."

In the early church, especially in the East, the word was used to describe any special gathering of bishops to decide important matters of faith, morality and church discipline. Synods always have been a privileged place for the development of the local churches in Eastern Christianity. Still today the election of Eastern Orthodox bishops takes place in synods.

A debt of gratitude is owed to Pope Paul VI because in 1967 he established the Synod of Bishops in the contemporary Catholic Church.

According to the 1983 Code of Canon Law, there are two forms of synods: the Synod of Bishops and a diocesan synod.

The majority of those who participate in a synod of bishops do so "ex officio," that is, they are present in their capacity as heads of Vatican offices and as presidents of bishops' conferences. A minority of other participants are personally invited to attend by the pope as he reserves the right to invite non-bishop participants such as priests, religious and lay faithful, especially if they are regarded as having a special competence or expertise in the topic under discussion.

While non-bishop participants at synods may make presentations upon invitation, only the bishops themselves -- and a few priests -- have the right to make direct interventions and to vote.

Furthermore, there is a distinction between an extraordinary synod and an ordinary synod, which meets at regular intervals. Presently, the Catholic Church, under the leadership of Pope Francis, is holding an extraordinary synod on the family, which will conclude with the beatification of Pope Paul VI (who reigned from 1963 to 1978) and will culminate in October 2015 with an ordinary synod on the family.

The work of the synod also will be highlighted by the World Meeting of Families to be held in Philadelphia Sept. 22-27, 2015, with organizers hoping that Pope Francis will attend.

The word "synod" is, in effect, synonymous with the word "council." The prototype of all church synods and councils is the Council of Jerusalem, which took place about 48 A.D. and is described in the 15th chapter of the Acts of the Apostles. At that council or synod the apostles -- under the leadership of Sts. Peter and James -- decided that Gentile converts to Christianity need not follow certain dietary and other laws prescribed in Jewish law.

Local diocesan synods or councils and meetings of the world Synod of Bishops are different from councils, like the Second Vatican Council, which are described as being "ecumenical," which means an international gathering of all the bishops in communion with the pope, the bishop of Rome.

The first ecumenical council in church history took place at Nicea in 325; it clarified doctrine about the divinity of Christ, and formulated what is now known as the Nicene Creed.

The first seven ecumenical councils took place before the Great Schism between the Christian East and West in 1054, and the seven are the only councils recognized by both the Catholic and Orthodox churches. The last of the seven was Nicea II held in 787, when the bishops defended the use of icons against the iconoclasts or those who destroyed icons because they considered them graven images and objects of idolatry.

In the ancient church, only the emperor could convoke an ecumenical council, with the first emperor to do so being Constantine the Great. However, the validity of the decrees issued by the councils always depended on their approval by the bishop of Rome, whose primacy in the See of Peter was never seriously questioned in the church of the first millennium.

The Catholic Church has invited Eastern Orthodox religious leaders and leaders of other ecclesial communities to attend synods and councils (as at Vatican II and many synods since then) although they do so only as auditors, possessing no right to vote. It is interesting to observe that the Protestant Reformers were even invited to the Council of Trent, an invitation they rejected.

Often, after the conclusion of a synod of bishops a final document, known as a "post-synodal apostolic exhortation," is issued by the pope.

The synod of bishops serves to foster greater communion and fraternity within the College of Bishops and to deepen the bonds of bishops with the pope, the Successor of Peter and visible head of the universal church.

Synods afford the world's bishops rare opportunities to pray together and to consult one another on important issues affecting the life of the church. However, the primary role of bishops at synods is to offer their counsel and expertise to the pope, bringing to the synod his own knowledge, ideas, pastoral experiences and the concrete concerns of the local church he represents and governs.

The pope encourages the bishops to hold frank and open discussions, demonstrating respect for each others' views on any given topic. At the conclusion of a synod, the fruits of the bishops' discussions are most clearly manifested in the pastoral and practical applications of timeless Catholic teachings which the bishops communicate to their collaborators, the priests, and through them to the lay faithful.

While the Catholic faith remains one and the same for all Catholics in every generation, the synod members strive to demonstrate through a series of presentations and small group discussions precisely how immutable Catholic doctrine and moral principles must be transmitted with compassion and full understanding for the real life pastoral needs of their own priests and lay faithful living in varying circumstances and conditions around the globe.

The church's view of the importance of the Christian family can be seen in the fact that a synod in 1980 already focused on it; the extraordinary synod is considering it; and the world Synod of Bishops convoked for Oct. 4-25, 2015, will continue the discussion.