Ed. note: Along the lines of Fr. Eckardt's Why? booklet explaining the parts of the liturgy, the Gottesdienst Online editors will be posting, in serialized fashion, explanations of words related to Christian worship - especially those of obscure derivation.
Once the wafer or loaf has been consecrated in a celebration of the Lord's Supper it is referred to as the host (beforehand it is altar bread, or simply bread). This term can be confusing to modern ears - perhaps calling to mind the relationship between parasite and host: as if the bread "plays host" to the Body of Christ; as if it were infected with the Body of our Lord.
In reality the latter usage (about host and parasite) derives from Latin hospes (guest-friend; Greek
Obviously, the development of host from hostia in the Latin speaking West is entangled with Medieval theories of the Mass as a sacrifice offered up by the priest. Nevertheless, the term has widespread use in Lutheran liturgical books down to the present day. Therefore, an evangelical understanding should be given to the term: what was once and for all sacrificed at Calvary is in reality upon the paten and in the mouths of all who receive this host. Indeed, an even stronger usage displayed in many Lutheran liturgical books (E.g. LSB p. 199) follows the example of the Small Catechism in simply referring to the host solely as the body of Christ.