Are there web-site with description of visual meaning of symbols? I'm interested in explanation of why certain symbol means what it means, in other words what object or scene it depicts. There is some books about that, like "Origin and evolution of...", but I wonder if there's way to get that information for free - some website.
this is an online dictionary you can search for certain words. 
http://www.vividict.com/ 

And I hope this includes symbols you want to know..