The word ecumenical comes from a Greek word that means pertaining to the whole world. It primarily describes a pluralist religious ethic, though in Christianity it only applies to the Christian church, and describes the pursuit of unity in the Christian world, between Christian denominations, and the universality of the Church.
It is expected that the new pope will work with all the rites (Cambrian, Byzantine, etc.) in a new search for the ecumenical ideal.
Hinduism is a religion that is inherently ecumenical and teaches a fundamental doctrine of multilateralism in regards to truth and spirituality. Hinduism teaches that, in essence, all religious, philosophical and spiritual paths when followed with a common base of human morality and love will reveal truth to the seeker, regardless of professed creed.
See also Ecumenism.