What is the full form of SEO?

SEO stands for Search Engine Optimization technically.

Practically to me, it stands for "Site Experience Optimization".

I say so since as search engines have evolved and matured, their ability to understand a website has gone up drastically leaving less and less work to do with the sole objective of making a page understandable to search bots. As technology continues to evolve, progression in processing power (Moore's Law still holds true), natural language processing capabilities, cognitive capabilities, and artificial intelligence is making search bots understand pages and their context better each year.

In fact, search bots are expected to bypass human capabilities in understanding context, meaning, and sentiments (add to it that they read a lot faster than humans and have a memory). All of this is leaving fewer things to optimize on a page for search bots that are not for human readers making SEO an act of site experience optimization. Fundamentally search engines are trying to rank the most engaging and relevant sites for a search term and are increasingly incorporating usage and engagement metrics in their algorithms. These days even if a site is able to hack its way into a top ranking, it does not stay there long unless the users engage with it. So optimizing for search engines is really optimizing for site experience. Great pages that engage and get shared will always make their way to the top. Site experience optimization is the holy grail of SEO and what SEO means for all practical purposes.