What is the difference between a used car and certified used car?

Marketing. It means some company wrote up a check list that they say makes it certified. So if BMW headquarters makes up a list, and dealer checks it off, it is certified 'by BMW standards'.

Kind of like the Academy Awards - a self serving item so a company can promote themselves.

I'm an officially certified Ski Bum. I wrote the list of what it takes to certify a ski bum, and had my son check it off for me. Great marketing.

What would you like to be certified in? That's how much it means.