Very early, the better to signify the gift of the Holy Spirit, an anointing with perfumed oil (chrism) was added to the laying on of hands. This anointing highlights the name "Christian," which means "anointed" and derives from that of Christ himself whom God "anointed with the Holy Spirit." This rite of anointing has continued ever since, in both East and West. For this reason the Eastern Churches call this sacrament Chrismation, anointing with chrism, or myron which means "chrism." In the West, Confirmation suggests both the ratification of Baptism, thus completing Christian initiation, and the strengthening of baptismal grace - both fruits of the Holy Spirit.
Source: Catechism of the Catholic Church (Vatican.va)