Ecumenism (/ɪˈkjuːməˌnɪzəm/ ih-KEW-mə-niz-əm; alternatively spelled oecumenism) – also called interdenominationalism, or ecumenicalism – is the concept and principle that Christians who belong to different Christian denominations and theological traditions should work together to develop closer relationships among their churches and promote Christian unity. The adjective ecumenical is thus applied to any non-denominational or inter-denominational initiative which encourages greater cooperation and union among Christian denominations and churches. Ecumenical dialogue is a central feature of contemporary ecumenism.
The fact that all Christians belonging to mainstream Christian denominations profess faith in Jesus, believe that the Bible is inspired by God, and receive baptism according to the Trinitarian formula is seen as being a basis for ecumenism and its goal of Christian unity. Ecumenists cite John 17:20–23 as the biblical grounds of striving for church unity, in which Jesus prays "may all be one" in order "that the world may know" and believe the Gospel message.