What is the short form of conversation?

There isn't really a single, universally accepted short form for "conversation." However, depending on the context, you could use:

Formal:

* Convo: This is a common informal abbreviation.

* Chat: This can be used for both informal and formal conversations.

Informal:

* Talk: This is a general term and can refer to any kind of discussion.

* Chit-chat: This refers to light, informal conversation.

* Dialogue: This is more formal, but can be used in informal contexts as well.

The best short form will depend on the specific situation and your intended audience.