A term in Google Analytics that helps webmasters classify where traffic is coming from (ie. the “source” of the web traffic).
In Google Analytics, the Source is the origin of the user prior to visiting a website for any type of traffic, whether it is organic, paid, social, referral, or direct.
Source can be a search engine (for example, Google) or a domain (website-example.com)
Examples include “google”, a visit originating from the search engine, “yelp.com”, a visit originating from a certain web page, or “direct” a user typing in the URL of the visited website directly into the browser.