A used car is a car that has been previously owned by someone else. Or it may be a car you have owned from new that you now want to sell on.
If you are looking for car finance or a car loan things may be easier if you are already driving a used car.
The car may be used to trade in to reduce the price to be paid or you may just sell the car to raise a deposit.
If you are re-scheduling your debt then in some circumstance a car may be used as security for a new loan.