AMP (Accelerated Mobile Pages)
AMP (Accelerated Mobile Pages) is an open-source framework co-developed by Google and launched in 2015 for very fast-loading, heavily simplified mobile web pages built on a restricted subset of HTML, CSS and JavaScript. It carries no special status in Google Search today: according to Google Search Central, AMP pages are indexed "just like other web pages", and Google applies "the same standard to all pages, regardless of the technology used to build the page".
In practice
Do not expect a ranking advantage from AMP: Google judges AMP pages by the same standard as every other page, so the usual SEO fundamentals simply apply. AMP is also no longer a requirement for inclusion in the Top Stories carousels. Modern responsive design with good Core Web Vitals scores reaches similar speed targets without the restrictions of AMP, so most new projects can do without it.