Listings on search engine results pages (SERP) that appear because of their relevance to the search terms.
Achieved without directly paying the search engine.
The entire field of search engine optimization is dedicated to improving the performance of organic listings on the SERP. The best way to improve a site’s organic listing position is to implement white hat SEO techniques on the website. In contrast, non-organic (paid) search results appear because a monetary bid was made on the search terms.