how would you explain seo content to a client?

I'd also tell them early what it isn't. Clients often expect it to mean repeating a keyword fifty times, or a blog post a week whether anyone searches for it or not. Saying up front that we only write things someone is actually looking for saves an awkward conversation three months in.

I tell them it's content written to answer what their customers are already typing into Google, so the right people find them without paying for every click. Then I show them one real search term and who ranks for it. That lands better than any definition.