Domain authority is a measure of the power of a domain name and is one of many search engine ranking factors. Domain authority is based on three factors: Age, Popularity, and Size. SEO gurus Moz can be credited with the metric known as DA or domain authority.
Page Authority is a score (on a 100-point scale) developed by Moz that predicts how well a specific page will rank on search engines. It is based off data from the Mozscape web index and includes link counts, MozRank, MozTrust, and dozens of other factors.
Google Page Rank
PageRank is Google's ranking software that calculates the relevance of a webpage to the search keywords entered. The software analyses both the number of incoming links and the 'quality' of the referring webpage to generate a relative measurement between 0 (low-relevance) and 10 (high-relevance).