What does "demo" mean? A few years ago, it meant, "demo" of a prototype, feature, or a product, i.e., a demonstration. The I renovated my apartment and when the contractor said, we "demo" the place, I learned that it meant "demolish". Now I hear at work how a strategy may "demo" ads, and I realize that means "demote". How can one to quickly find out how many words in the dictionary begin with prefix "demo" and what is the prefix that comes after the prefix "demo"?