Some useful definitions:
Dialogue is when persons of different viewpoints come together and interact.
Interfaith dialogue is when persons of different faith traditions or broader religious families interact.
Intrafaith dialogue is when persons within a traditions come together with other persons of that faith tradition.
Interreligious dialogue is the formal encounter between representatives of different religious communities.
Ecumenism is when Christians from different sects of movements within Christianity come together.
Multifaith is when people of different religions come together without special attention to their individual religions.
From Heckman, 2008