A back link may refer to any of the following:
1. Alternatively referred to as an inbound link, incoming link, or inlink, a back link or backlink is any hyperlink that links from a web page to another web page on another site. Search engines like Google count the number of backlinks to a page to help determine its popularity. For example, if two pages have similar content but one page has 100 backlinks and the other has 3, the page with 100 backlinks may rank higher on a SERP.
2. A back link is any link that takes a website visitor back to the page that linked them to the current page. With HTML, to create a back link button, use the source code shown below.
<input type=button value="Go Back" onClick="history.go(-1)">
Entering the code above would create a button similar to the example below. Clicking the button below makes the browser go back to the page that linked to this page. For example, if you reached this page from a search engine, it would return you to the search results page.