According to Roman Catholic Church teaching, a sacramental character is an indelible spiritual mark (the meaning of the word character in Latin) imprinted by three of the seven sacraments: Baptism, Confirmation, and Holy Orders.
|“||The three sacraments of Baptism, Confirmation, and Holy Orders confer, in addition to grace, a sacramental character or seal by which the Christian shares in Christ's priesthood and is made a member of the Church according to different states and functions. This configuration to Christ and to the Church, brought about by the Spirit, is indelible; it remains for ever in the Christian as a positive disposition for grace, a promise and guarantee of divine protection, and as a vocation to divine worship and to the service of the Church. Therefore these sacraments can never be repeated.||”|
The characters these three sacraments imprint are held to differ from each other, with each character remaining indelible, so that nobody can receive the sacrament in question more than once. The doctrine of the sacramental character is thus a particular expression of the long-established teaching that baptism, confirmation, and holy orders may not be repeated, e.g. no one may be baptized more than once.
One who receives a lower grade of holy orders may receive a higher. Thus, though one who has been ordained a deacon may not again be ordained a deacon, he may be ordained a priest. Similarly, while a priest may not again be ordained a priest, he may be ordained a bishop. There is no higher grade to which a bishop may be ordained. Each higher grade is considered to confer a deepening or intensification of the character of holy orders.
If it is doubtful whether a person has received one of the three sacraments in question, the sacrament may be administered conditionally (using words such as "If thou art not baptized, I baptize thee in the name of the Father and of the Son and of the Holy Spirit"); but such an administration, being valid and effective only to the extent that no valid administration of the same sacrament has already occurred, does not in any event constitute an effective repetition of a valid previous administration of that sacrament.
The Catechism of the Catholic Church, 698 explains as follows the significance of the image of "seal", used as an alternative to that of "character":
|“||'The Father has set his seal' on Christ (John 6:27) and also seals us in him (cf. 2 Corinthians 1:22; Ephesians 1:23, 4:30). Because this seal indicates the indelible effect of the anointing with the Holy Spirit in the sacraments of Baptism, Confirmation, and Holy Orders, the image of the seal (σφραγίς) has been used in some theological traditions to express the indelible 'character' imprinted by these three unrepeatable sacraments.||”|