Authority
Authority describes how much trust a site or page has earned in the eyes of search engines, mostly through quality links and consistent subject expertise. Google publishes no authority score, so the numbers marketers quote come from third-party tools estimating it.
Why it matters for your rankings
Authority is why two pages with near-identical content rank differently. The one on a site with a stronger track record wins, because search engines treat past performance as evidence of future reliability.
It compounds, which makes it strategically important. Each quality link makes the next page easier to rank, which earns more links. That is why established sites outrank better content from newer ones, and why patience matters more than tactics early on. The failure mode is treating a vendor score as the goal. Domain Authority and Domain Rating are estimates, not the thing itself. A site can raise them with links that do nothing for revenue. The useful question is whether you are trusted on your specific subject, not whether a number rose.
How to check it on your site
Record your baseline
Note your Domain Rating in Ahrefs and Domain Authority in Moz today, so later movement is measurable rather than remembered.
Compare referring domains, not links
In Ahrefs open Referring Domains for you and three competitors. The count of distinct linking sites predicts ranking ability far better than total link count.
Assess topical concentration
Check whether your links come from sites in your industry. Fifty relevant links beat five hundred random ones.
Look for authorship signals
Confirm your key content carries named authors with real credentials and bio pages. This is what Google's raters are told to look for.