E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness: the qualities Google's quality rater guidelines use to describe helpful, reliable content.
It isn't a single score. It describes signals like first-hand experience, a clear author or company behind the content, and a site others trust and cite.
Trust is treated as the most important part.
Why it matters for a launch
Writing from real experience, saying who is behind a product and earning mentions on trusted sites helps new sites look credible to search engines and readers.