Here is a 75-word description of SEO:
"SEO (Search Engine Optimization) is the process of improving the visibility and ranking of a website in search engine results pages (SERPs) through various techniques. It involves optimizing website content, structure, and coding to make it more search engine-friendly, increasing the quality and quantity of website traffic from search engines like Google, Bing, and Yahoo. The goal is to drive more organic traffic to a website, increasing online visibility and credibility."