A certified pre-owned model is still a used car, but a used car is not a certified pre-owned vehicle. A CPO model has passed a thorough inspection and had restoration work done to meet the standards of the certification. Certified pre-owned models also have things like mileage requirements, often coming in under 100,000 miles or so. It also comes with a warranty and other benefits, depending on the brand that is certifying the vehicle. On the other hand, a used car comes as-is with the remainder of its factory warranty—if it's even transferrable or still valid.