The new translation of the Roman Missal has expanded our liturgical vocabulary to more fully express what happens in the Church’s liturgy. Father Jungmann, in The Mass of the Roman Rite, discusses the various names by which the Mass has been referred in different places and times. In so doing, he comments on the distinction between offering and sacrifice. Father Jungmann notes that these words stem from the Latin oblatio and sacrificium which are forms of offerre and sacrificari. Offering refers an action, specifically the free giving a particular object. Thus a sacrifice is offered to a deity. Typically, when the Mass is called a sacrifice, sacrifice is used as an object with a meaning closer to that of oblation. However, sacrifice differs from oblation because a sacrifice is completely offered up and more or less destroyed. Jesus the Great High Priest (cf Hebrews 4:14) offered his sacrifice on the cross to the Father. The object which was sacrificed was his very self. Jesus is both priest and victim: priest because he is the one who offers the sacrifice, victim because he is the one who died on the cross. Since Holy Mass is the same sacrifice which Our Lord offered on Calvary, then both of these terms can aptly describe Holy Mass.
Father Jungmann goes on to describe other names of the Mass, but brevity and time keeps me from discussing them here.