What in the world is bump? i see people doing it on forums all the time. Can someone explain?

Hello there!

I think the word ‘bump’ means: to move the topic to the first page (It ‘bumps other topics’).

Does that answer your question?

BUMP means “Bring Up My Post”, it's used to bring a topic back to the front page so that it garners more attention, though there is a general limit as to how often you can bump a post.
No, I was not ninja'd, I saw the post above me

Whenever a topic is posted on it is moved up to the front page of the forums, and people will “bump” a topic by posting on it if it's still relevant and has a reason to be bumped. There is a Wiki article on it

It moves up your forum topic like any other post

Bump stands for “bring up my post”. It “bumps” your post to the top of the page.