CPO stands for "Certified Pre-Owned". It is a term used to describe a type of used car that has undergone a thorough inspection and repair process, and comes with a manufacturer-backed warranty. CPO cars are often trade-ins or leased vehicles that have been returned to the dealer. The advantage of purchasing a CPO car is that youre buying a used car thats been thoroughly vetted rather than a standard car with an unknown past. CPO programs vary among manufacturers, so its important to compare programs to determine what best represents your needs and expectations. In addition to cars, the term "CPO" can also be used in references to guns and phones.