What is a JavaBean exactly

Question

I understood, I think, that a "Bean" is a Java-class with properties and getters/setters.
As much as I understand, it is the equivalent of a C struct. Is that true?

Also, is there a real syntactic difference between a JavaBean and a regular class?
Is there any special definition or an Interface?

Basically, why is there a term for this?

Also what does the Serializable interface mean?