Ecumenism: A movement promoting unity among Christian churches or denominations.
Excerpt from Conciliar Decree on Ecumenism:
"Before the whole world let all Christians confess their faith in the
triune God, one and three in the incarnate Son of God, our Redeemer and
Lord. United in their efforts, and with mutual respect, let them bear
witness to our common hope which does not play us false. In these days
when cooperation in social matters is so widespread, all men without
exception are called to work together, with much greater reason all
those who believe in God, but most of all, all Christians in that they
bear the name of Christ. Cooperation among Christians vividly expresses
the relationship which in fact already unites them, and it sets in
clearer relief the features of Christ the Servant. … All believers in
Christ can, through this cooperation, be led to acquire a better
knowledge and appreciation of one another, and so pave the way to
Christian unity."
Unitatis Redintegratio, n. 12.