My convertism is showing: what’s a subdeacon?
Depends a bit. In priestly formation pre-V II, and in the Eastern Churches in union, a man recieves first minor orders, then subdeacon, then deacon (diaconos), then finally presbyter (priest, sacerdos).
The Roman Minor Orders were Lector, Acolyte, Porter and in some times Porter, Exorcist and Cantor were minor orders. Individuals were said to be ordained to these orders, which are ancient but not of biblical origin.
In the Roman Rite, the subdeacon was considered a major order until Vatican II. It was abolished by HH. Paul VI, and Lector and Acolyte ceased being ordained, but are now instituted (ceremony is almost identical, tho’), and not considered to have entered the ranks of the clerks. (IE, they’re still laymen by canon law.) The term Subdeacon may be used for instituted acolytes with the permission of their instituting bishop. (Some only permit it for men holding institution into both the order of Lector and Acolyte)
In the Eastern Rites and their constituent churches, subdeacons are a minor order, and the minor orders are still used, and clerks (those ordained to minor orders) have a separate status from laity under canon law, are incardinated as minor clergy, and subject to obedience in the same way as secular clergy, tho’ to a lesser extent.
Deacons, priests, and bishops are all major orders. Major orders are of biblical origin. Bishops are of Apostolic origin, and noted in Acts and the letters of Paul. Presbyters are mentioned often in the Pauline letters. Deacons were noted in Acts as to their creation by the apostles.
Deaconesses are no longer ordained, and their status is of much debate.
The Subdeacon performs several specific tasks in the high mass - chanting the epistle, holding the book of the gospels when the deacon chants the gospel, performing the lavabo (washing the priest’s hands), and serving as a regular extraordinary minister of communion, carrying the sacred vessels to the deacon, and a few other odd bits. All of the subdeacon’s tasks in the Roman liturgy may now be performed by instituted acolytes.
Note that the SSPX still ordain subdeacons separately from acolytes, and still ordain acolytes.