What is an "open date of return?"?

If I buy a roundtrip plane ticket that has an "open date of return," what does that mean?|||It means that you can book your return trip for whenever you want. However those types of tickets do not exist. In the past, you can buy open ended tickets, but nowadays, the airlines make you have a return date.|||As mentioned the day's of the open return have gone , but you can book your return flight and alter it at your outgoing destination . Ask when booking and make sure that it can be changed , it is usually a small fee to change your return but give them notice .|||Its mean that return part of ticket is not fixed and you can adjust a per your schedule. It will avoid any cancelation charges or date change charges. In our company we send our engineer team by open date of return ticket so they adjust it as they complete work