In Christian theology, a sodality, also known as a syndiakonia, is a form of the "Universal Church" expressed in specialized, task-oriented form as opposed to the Christian church in its local, diocesan form (which is termed modality). In English, the term sodality is most commonly used by groups in the Anglican Communion, Catholic Church, Eastern Orthodox Church, Lutheran Church and Reformed Church, where they are also referred to as confraternities. Sodalities are expressed among Protestant Churches through the multitude of mission organizations, societies, and specialized ministries that have proliferated, particularly since the advent of the modern missions movement, usually attributed to Englishman William Carey in 1792.
In many Christian denominations, "modality" refers to the structure and organization of the local or universal church, composed of pastors or priests. By contrast, parachurch organizations are termed sodalities. These include missionary organizations and Christian charities or fraternities not linked to specific churches. Some theologians would include denominations, schools of theology, and other multi-congregational efforts in the sodality category. Sodalities can also include religious orders, monasteries, and convents.
The sodalities of the Church are pious associations and are included among the confraternities and archconfraternities. Joseph Hilgers, writing in the Catholic Encyclopedia, states that it would not be possible to give a definition making a clear distinction between the sodalities and other confraternities. Confraternities and sodalities had their beginnings after the rise of the confraternities of prayer in the early Middle Ages (around 400–1000 AD), and developed rapidly from the end of the 12th century, with the rise of the great ecclesiastical orders, such as the Dominicans, the Carmelites, and the Servites. Other associations of this kind soon appeared under the jurisdiction of the local ordinary and had no particular connection with a religious order.