What is an informal talk called?

There are many informal terms for a talk, depending on the context and tone:

General terms:

* Chat

* Presentation

* Discussion

* Lecture (though this is usually more formal)

* Speech

* Talk

* Address

* Keynote

More specific terms:

* Briefing (informal presentation of information)

* Workshop (interactive discussion with audience participation)

* Seminar (focused discussion on a specific topic)

* Fireside chat (informal conversation with an expert)

* Meet-and-greet (informal gathering with networking)

Slang terms:

* Rambling

* Spilling the beans

* Sharing my thoughts

* Giving a run-down

The best term to use depends on the specific situation. Consider the speaker, the audience, the topic, and the overall tone of the event.