The meaning of the Holy Eucharist.

The Eucharist /ˈjuːkərɪst/, also called Holy Communion, the Sacrament of the Altar, the Blessed Sacrament, the Lord's Supper, and other names, is a Christian sacrament or ordinance.

It is reenacted in accordance with Jesus' instruction at the Last Supper, as recorded in several books
of the New Testament, that his followers do in remembrance of him as when he gave his disciples
bread, saying, "This is my body", and gave them wine saying, "This is my blood."[2][3].

In spite of differences between Christians about various aspects of the Eucharist, there is,
according to the Encyclopædia Britannica, "more of a consensus among Christians about
the meaning of the Eucharist than would appear from the confessional debates over the
sacramental presence, the effects of the Eucharist, and the proper auspices under which
it may be celebrated."[2].

The word Eucharist may refer not only to the rite but also to the consecrated bread (leavened
or unleavened) and wine[4] (unfermented grape juice in some Protestant denominations,
water in the LDS church) used in the rite. In this sense, communicants (that is, those who
partake of the communion elements) may speak of "receiving the Eucharist", as well as
"celebrating the Eucharist".

Reference:
http://en.wikipedia.org/wiki/Eucharist