What is a referrer URL?
A referrer URL is the address of the webpage where a person clicked a link that sent them to your page.The referrer is the webpage that sends visitors to your site using a link. In other words, it’s the webpage that a person was on right before they landed on your page.
Referrer URLs are logged by many web analytics programs including Google Analytics. You can monitor these URLs to get insight into where your web traffic is coming from.