1. A casual greeting or conversation starter, somewhat of a rhetorical question.
Usually followed by something like "Not much, you?," "Nothing much," or even answered with a "Hey man, how's it going?"
syn: How's it going? What is new?
2. syn. What can i do for you?, What would you like? What's on your mind?
1. Person #1: Hey There! What's up?
Person #2: Oh not much. What's up with you?
2. Person #1: Hey come here for a second, I have to ask you something.
Person #2: Ok, what's up?