DALMATIC

The outer vestment worn by deacons during Mass. Unlike the chasuble, it has sleeves and opens at the sides, reaching below the knees. Typically, the color and decoration of the dalmatic will match (or be similar to) the chasuble worn by the priest.

CASSOCK

A black/white garment that reaches to the feet that buttons up the middle. 

When worn with the roman collar, it is a clerical garment, although in some places it may be worn by a server, master of ceremonies, or cantor without the roman collar. The cassock itself is not a vestment but is often worn underneath the alb. Colors other than black in a cassock denote office (for monsignors, bishops, cardinals, and popes). It can also be worn with a surplice, which is a white, large-sleeved, loose fitting garment that reaches tothe knees (looks like a cutoff alb).

COPE

A long semicircular cloak, usually richly ornamented, open in the front and fastened at the breast by a chain or clasp and reaching to the knees, this vestment is never worn  during Mass but during other liturgical occasions by clergy. 

HUMERAL VEIL

An oblong, rectangular cloth that is placed over the shoulders and clasps in front of the chest. It is used during Benediction of the Blessed Sacrament as well as during the procession of the Blessed Sacrament or during the transfer of the Eucharist from one tabernacle to another.