The priest’s vesture:
Amice – Symbol of the helmet of salvation: The amice is a rectangular piece of white linen with two strings at the upper corners which a cleric uses underneath his alb to cover the neck so that the Roman collar of the cassock is hidden. The word amice comes from the Latin amicire, meaning “to cover” and, because the heads of criminals condemned to death were covered in linen, the amice recalls the humiliation which was put upon Christ.
Alb – Symbol of purity: The alb is the long white, robe-like vestment worn by all clerics at liturgical celebrations (celebrant, concelebrant, deacon, or acolyte). The alb (from Latin word alba, meaning “white”) can be traced to the ancient Roman alb worn under a cloak or tunic; its color symbolizes purity and its form recalls that described in Ezekiel 28:4.
Stole – Symbol of the clerical office, immortality, and the yoke of Christ: The stole, matching the liturgical color, is a long, scarf-like vestment worn over the alb and under the dalmatic/chasuble. The priest wears the stole around his neck so that it hangs equally down his chest in front or forms an X-shaped Cross; the deacon wears his stole over the left shoulder and tied at his right side; the Bishop wears his stole so that it hangs equally down his chest. As he puts on the stole, the priest kisses the Cross.
Chasuble: Symbol of being housed by Christ: The chasuble, also matching the liturgical color, is is the long, often ornate, sleeveless poncho-like garment worn by priests and bishops over the alb and stole during the sacrifice of the Mass.
Biretta: The biretta is a tri-cornered or square-shaped hat with silk trim, tuft (except for the birette of seminarians and cardinals) and three raised wings, called “horns,” on top at three corners (the side of the hat without the horn is worn on the left side of the head). It is made of scarlet silk for cardinals, violet silk for bishops, and black merlino for priests, deacons, and seminarians.