Here is what Merriam-Webster says:
or more characters are represented as conversing
2a: a conversation between two or more persons; also a similar exchange between
a person and something else (as a computer)
b: an exchange of ideas and opinions
c: a discussion between representatives
of parties to a conflict that is aimed
4: a musical composition for two or
more parts suggestive of a conversation.
While this is an adequate description of “dialogue” I want to highlight a few things that I think are essential to recognize about dialogue.
I think the M-W’s 4th definition is a great way to think of dialogue because music and art is concerned with the process of composition and not about the final project. That is why U2, Phish, Elvis, Mozart, etc. repeatedly played their musical compositions. Each time, in each setting, a new “voice” was added to their dialogue.
wb:Dialogue is the process of creating a form of communication that relies upon more than one person with a variety of perspectives, which leads towards a richer understanding of each other and oneself.