A "dance floor" is an indoor area where people are dancing (or where they're supposed to dance).

When you're in a situation where there's dancing going on, you can talk about the things that are happening "on the dance floor". Here are some things that people do on the dance floor:

• get out on the dance floor (start dancing)
• get down on the dance floor (dance enthusiastically)
• go crazy on the dance floor (dance wildly)
• see someone on the dance floor