Catechism of the Catholic Church
“The inexhaustible richness of this sacrament is expressed in the different names we give it. Each name evokes certain aspects of it. It is called: The Breaking of Bread, because Jesus used this rite, part of a Jewish meat when as master of the table he blessed and distributed the bread, above all at the Last Supper. It is by this action that his disciples will recognize him after his Resurrection, and it is this expression that the first Christians will use to designate their Eucharistic assemblies; by doing so they signified that all who eat the one broken bread, Christ, enter into communion with him and form but one body in him.”
Source: Catechism of the Catholic Church #1328-9