What’s the Difference between a sign and a symbol?

What’s the Difference between a sign and  a symbol?
Signs –	Objects or gestures that express ONE specific message or meaning. For example  Stop sign.
Why do we need symbols?
Words alone are not enough to describe the desires, fears and emotions that touch us deeply.
Words / feelings / ideas that are intangible (hard to describe) are associated with something that is tangible (easily recognized; can be touched). For example  a flower can represent love, friendship, beauty or new life.