Signs create meanings by invoking comparisons with other signs. Signs 'stand for' other signs. This comparison between and among signs is often referred to as metaphor . A metaphor stands in for something else. Often used to express, or create, an idea.
Symbols are akin to metaphor.
The symbol 'stands for' something. Some symbols are more universally applicable than others. However, anybody who has struggled with symbols when travelling overseas will appreciate the cultural coding implicit in symbols. Symbols may also create meaning in a less direct, or less overt, manner. Consider the cultural coding of such symbols and their relationship to power.