Definition - What does Domain Authority mean?
Domain authority measures how well a particular domain page will rank, absent any other critical factors like content and rich media. It is the core valuation of how much value is in that particular domain URL. Domain authority emerged from Google PageRank practices, and now gets analyzed by various firms and vendors in SEO and page ranking services.
Domain authority is also known as site authority or thought leadership.
Techopedia explains Domain Authority
The idea of domain authority is that more established websites accrue domain value. The SEO company or other party uses evaluation tools to figure out the domain authority score, which is often measured on a scale from 1 to 100. Other factors also influence Google page ranking, but companies measuring domain authority can tell clients more about how any given page will rank. The best domain authority measurements bring many different metrics to the process, to figure out how valuable a particular domain URL is to its holder.