what does "bump" mean?

It's basically adding a comment to a thread that adds no substance to the thread. It is used for 2 reasons, 1) To bump the thread back up to the top of the recent posts page so more people see it if the thread has gone cold. 2) For someone to bump and post on a thread so they can later go back in their own post history to read the rest of the thread because it was something they were really interested in.

Glad you asked. I was wondering the same thing.

I thought it was like a fist bump, high 5 kind of thing!! : ^ D