Trying to understanding stats associated with website

Can you help? I am trying to understand some statistics associated with my website traffic. When I look at the 'Referrer Type' I get the follows stats:

 Referrer types
• Direct traffic 57.4%
• External URL 25.3%
• Social Networks 13.7%
• Search engine 3.4%
• Search engine spiders 0.1%
• News Message 0.1%

What is an example of 'Direct traffic' versus 'External URL'?

How does 'Direct traffic' and 'External URL' differ from 'Social networks'? Can direct traffic and an external URL come from social media posting?

Does 'Social Networks' mean all traffic generated from the likes of Facebook, LinkedIn, Twitter, etc.?

What is an example of 'News Message'?

Any insights you can provide will be most helpful.

Sincerely,

Robert