Hypertext links from 3rd party web pages on the internet to your own content. Backlinks are one of two core elements of the Google algorithm. Sites with a larger number of backlinks from high quality websites will rank higher than sites with few backlinks, or backlines from low quality websites.
Domain Authority (DA)
A calculated estimate of how well your website will rank in search engines. The calculation is performed by Moz.com in an attempt to replicate the algorithms used by popular search engines like Google and Bing.
Page Authority (PA)
Similar to Domain Authority, this is a calculated estimate of well a specific page of your website will rank in search engines. It is calculated by Moz.com.