Can someone explain to me what arbitrary signs are and some examples.. The websites on google confuse me.. Does anyone know of any good sites?

In what context are you using "arbitrary signs?"

like maybe traffic signs for example

like the no entry sign might be arbitrary because it really doesn't say anything specific other than a symbol.

A stop sign isn't arbitrary because you are expected to stop

None of those are arbitrary. The graphics have meaning.

How about the dollar sign? -- $

# -- pound

= -- equal

how is a dollar sign arbitrary. I'm confused now

The dollar sign in itself has no meaning. It was arbitrarily chosen to represent the dollar.

http://www.history.com/news/ask-history/where-did-the-dollar-sign-come-from

OK so would like a yield sign be considered arbitrary?

The shape is arbitrary, but usually the word "YIELD" is on it.