Presider and celebrant are synonyms for the person who offers the Mass. Thus, only a priest or bishop can be a presider or celebrant. Presider is a newer term that is generally meant to indicate that the priest takes the lead in offering the Mass. Celebrant in of older vintage and indicates that the priest is the person who primarily celebrates the Mass. In recent times presider has become preferred by some as a means of indicating that the congregation should take an active role in the liturgy, proper to their status as laity; but either term is correct.
