On this same-day return trip, you must travel both ways with the same company. Departure and return times will be given to you at morning check-in.
A Round Trip is a travel type where both the outbound and return dates and times are known.
An Open Return trip has a set outbound date and time but an open return date. You do not need to specify the return date at the time of purchase; it can be changed later free of charge.
A One Way trip has a set outbound date and time only. It is company-independent.