Pre-own would mean to own before the current owner. It is sometimes used with regard to cars. They call them pre-owned vehicles instead of second hand cars to make them sound better. ( second hand has conotations of old and inferior) Its not really a word tk be uses in regular conversation.

I agree with timmy. It is what we call 'marketing - speak '. The original term' used cars ' implied that they had been worn, it emphasised their prior use. Pre owned shifts the emphasis away. Sometimes you will see a similar term ' pre - loved ' though not so likely in a professional manner, maybe in a private sale.