In
Christian ecclesiology,
full communion is a relationship between church organizations or groups that mutually recognize their sharing the essential doctrines. As a practical matter for most Catholics, this affects whether or not a member of one Church may partake of the
Eucharist celebrated in another, and for priests, whether or not they may
concelebrate the Eucharist with priests of another Church. In each case, if the two Churches are in full communion, then they may.