Topical Authority is a term in search engine optimization where a site covers every possible aspect of topic across several pages through internal linking in order to signal to Google or other search engines that it is the topical authority on a subject. Quality and quantity of the content produce surrounding a certain keyword help increase topical authority. Topical Authority has been studied in its ability to outperform backlinks and preferred technique for those new to SEO. Backlinks are harder to acquire than topical authority as it requires other parties agreeing to put links to your site on their site, where as topical authority is all about providing as much content as possible around a certain keyword, and using good internal linking to connect the content, let search engines know your understanding of a certain key word and all its adjacent topics.
Topical Authority Changes the Game - Interview with Koray Tugberk
Nick Jordan Grows Sites to Over 100k Organic Views a Month No Link Building