The Synod of Bishops is an advisory body for the Pope. It is described in the Code of Canon Law (CIC) as “a group of bishops who have been chosen from different regions of the world and meet together at fixed times to foster closer unity between the Roman Pontiff and bishops, to assist the Roman Pontiff with their counsel in the preservation and growth of faith and morals and in the observance and strengthening of ecclesiastical discipline, and to consider questions pertaining to the activity of the Church in the world.”

The Synod of Bishops is permanent, even when not in session. Periodically, it holds assemblies, which are either general, if called to consider matters directly concerning the universal Church, or special, if called for problems of a particular geographical area. The general assemblies are either ordinary (held at fixed intervals) or extraordinary (held to treat of some urgent matter).

The Synod of Bishops also has a permanent secretariat[6] headquartered in Rome but is not part of the Roman Curia. Pope Francis greatly increased both the authority and influence of the Synod in September 2018.

from Wikipedia

See also documents authored by Synod of Bishops