Sacramental bread (Latin: hostia), sometimes called altar bread, Communion bread, the Lamb or simply the host, is the bread which is used in the Christian ritual of the Eucharist. The word 'hostia' is Latin for sacrificial animal. The sacrifice of Jesus according to Christian theology puts an end to the need for animal sacrifice as had been practiced in the Jerusalem Temple and all blood sacrifice once-for-all. The word was retained to describe the bread of Eucharist as a liturgical representation of the Christ's sacrifice.
The Orthodox Church and Eastern-rite Roman Catholic churches use leavened bread for the Eucharist. Thus, the sacramental bread symbolizes the Resurrected Christ. The hostia or sacramental bread, known as prosphorá or a πρόσφορον (prósphoron, "offering") may be made out of only four ingredients: fine (white) wheat flour, pure water, yeast, and salt.
Sometimes holy water will be either sprinkled into the dough or on the kneading trough at the beginning of the process.
The baking may only be performed by a believing Orthodox Christian in good standing—having preferably been recently to Confession, and is accompanied by prayer and fasting. Before baking, each loaf is formed by placing two disks of dough, one on top of the other, and stamping it with a special liturgical seal. The prosphora should be fresh and not stale or moldy when presented at the altar for use in the Divine Liturgy. Often several prosphora will be baked and offered by the faithful, and the priest chooses the best one for the Lamb (Host) that will be consecrated. The remaining loaves are blessed and offered back to the congregation after the end of the Divine Liturgy (Eucharist); this bread is called the antidoron (Greek: αντίδωρον, antídōron), i.e. a "gift returned", or "in place of the gifts".