What is Position 0?

Position 0, officially an Advanced Snippet from Google, is the name given to organic results that appear above the organic Position 1 in search results, often looking like this:
Advanced Snippet or position 0 in Google SEO
Position 0, in order to preserve Position 1, is the organic placement that appears below the Google Ad positions (typically position 3) and organic Position 1. Position 0 is often a much bigger result, can include a Question, Knowledge or Answer Panel and is frequently the focus for SEO’s around the world. Since January 2020, Advanced Snippets are no longer repeated in the regular top 10 search results on Page 1.