I’m guessing they meant SEO - Search Engine Optimisation. It’s much more complex than this, but essentially finding high volume search terms and writing website content based around those terms so your page shows up higher organically.

It’s why recipe pages or simple how to guides have paragraphs semi related text that sounds like it was written by committee. The content needs to be human readable, otherwise Google flags it as spammy, but at the same time it only serves to drive up clicks based on those search terms.