What does original miles mean on a car?

Answer 1

It does not mean anything. A car with 80,00 miles and 80,000 "original" miles are the same. Back before odometers registered more than 100,000 miles, the term "actual miles"was used on car titles in some states to indicate the odometer had not rolled over and started again.

Now it's a useless term a used by people who have seen it used by others sellers.

It is just another way of saying "actual" miles. If you replace an engine it is not going to be the same mileage as the odometer says. Also replacing the transmission wont be original/actual mileage. Original mileage means actual mileage on all the main components of the car. It is just terminology used for sales.