The priest is a is a member of the clergy who has been through the minor orders and ordained in all the major holy orders.
Priests make up 2-5% of the general population.
Minor orders are conferred upon those pursuing an education in the Church or specifically studying for the priesthood, involving first tonsure and ordination as either an Acolyte, Lector (one who reads), Ostiary (doorkeeper), or Exorcist. Of these, the Acolyte is the highest in prestige. These four are called “minor orders” because perpetual celibacy was not required of them.
Those studying for the practice of law rarely go beyond minor orders in their career path unless they specialize in canon law or civil law. No prospective clergyman would take further vows (major orders) in the church unless a benefice was offered for his maintenance.
The usual minister bestowing minor orders was a bishop; but some abbots could give the tonsure and minor orders to their subjects.
After receiving all the minor orders, the clergyman could receive ordination in the major orders.
The major orders are the final ones: Subdeacon, Deacon, and finally Priest. The reason these orders are considered “major” is with ordination to the subdiaconate, both the recitation of the Liturgy of the Hours (the Divine Offices) and perpetual celibacy become mandatory. An acolyte does not have to perform the Divine Office and can marry without Papal dispensation if he leaves his holy course of study before becoming a subdeacon.
Neither the minor orders nor the subdiaconate are considered a part of the sacrament of Holy Orders, but are instead viewed as preparatory offices to the priesthood.
The parish priest is in charge of a town or village chapel or church and its parish, generally equal to a whole large village/small town or collection of small villages, generally encompassing about 100 families. He is responsible for teaching the congregation the equivalents of the Paternoster, Ave, Creed, and the seven (or nine) Virtues and deadly sins four times during the course of the year. He is supported by the tithes and the proceeds of the glebe lands allotted to his church, which he must help work with his own hands, right alongside the common farm folk of his parish. The house appendant to the church in the priest’s care, in which he lives, is called the parsonage.
A monk or priest who dwells exclusively in a religious house of some sort, either in a town or a rural setting, who is unable to come or go except by the permission of his abbot/prior (monks) or Father/Mother Superior (priests) is called “cloistered”.
A rector is a type of priest appointed to take care of a church that does not belong to either a parish, a chapter of canons, or a religious order. Thus, he is not the parish priest, his church is not be the central parish church or belong to a religious house or community, though he may have charge of a seminary or university college. A rector is not allowed to perform baptisms, confirmations, anoint the sick, or conduct a marriage or funeral without the permission of his parish priest except in an emergency. His regular duties are comprised essentially of regular masses, taking confessions, teaching (“song school”), and administration. Unlike the vicar who fills in for an absentee priest, to whom all excess income must be sent, the rector takes care of a satellite church of a parish founded because the population is too great for the parish church alone to serve its needs. He is allowed to manage the lands and income awarded to the rectory wholly on his own behalf and that of his congregation.
The chaplain/confessor is a priest or monk in the service of a noble family or higher clergyman, whose duties include performing private services for the family/household, supervising private devotions for family members, hearing confessions (as applicable) and also working as a scribe, bookkeeper or personal secretary. They are often assigned to individual members of the household, particularly the lady of the house, or the daughters, for whom they may also act as chaperone, or the eldest son and heir, also often filling the position of family tutor (“magister”).