Eucharist (also called Holy Communion or the Lord's Supper), the Christian rite involving the eating of bread and drinking of wine, reenacting the Last Supper
Communion (chant), the Gregorian chant that accompanies this rite
First Communion, a ceremony in some Christian traditions during which a person receives the Eucharist for the first time
Koinonia (communion or fellowship), the relationship between Christians as individuals and as churches
Communion of Saints, a doctrine of Christianity mentioned in the Apostles' Creed