(διάκονος, minister, servant), the name given to the lowest grade of office-bearers in the Christian church. From the appointment of the seven Hellenic deacons (Acts vi.) we learn that their duty under the apostles was simply to distribute alms from the public fund. In the early church, however, they soon came to usurp higher functions. They assisted the bishop and presbyter in the service of the sanctuary; in the administration of the Eucharist they handed the elements to the people; they instructed the catechumens; and in some cases baptized, and even exercised the judicial power of the bishop over the inferior clergy.

In the Church of England, the form of ordaining deacons declares that it is their office to assist the priest in the distribution of the holy communion; in which, agreeably to the practice of the ancient church, they are confined to the administering of the wine to the communicants. A deacon in England is not capable of any ecclesiastical promotion, yet he may officiate as a private chaplain, as curate to a beneficed clergyman, or as lecturer to a parish church. He may be ordained at twenty-three years of age, anno currente; but it is expressly provided that the bishop shall not ordain the same person a priest and deacon in the same day. In Presbyterian churches, as in apostolic times, the deacons have charge only of the pecuniary affairs of the congregation. In the Roman Catholic Church it is the deacon's office to incense the officiating priest or prelate; to lay the corporal on the altar; to receive the paten or cup from the subdeacon, and present it to the person officiating; to incense the choir; to receive the pix from the officiating prelate, and carry it to the subdeacon; and at the pontifical mass, when the bishop gives the blessing, to put the mitre on his head, and to take off the archbishop's pall and lay it on the altar.

in Scotland, also denotes the president of an incorporated trade.