It's a real YMMV on this. Some state one-way, some stay the other.
My one experience with such on a LONE4 had us scheduled to arrive on BA into LHR from ORD at 10am and departing for DBV from LGW at 10am the next day.
It was ticketed by AA as a transit (-ORD-xLON-DBV-).
Even with this AA can be non specific. e.g.
http://www.aa.com/i18n/Tariffs/AA1.h...IRY_AA1-0135AA
Originally Posted by definitions
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Transit Point means any stop at an intermediate point on the route to be traveled (whether or not a change of planes is made) which does not fall within the definition of a stopover.
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Stopover means (Not applicable between points in Canada and points in Puerto Rico/Virgin Islands) a deliberate interruption of a journey at an intermediate point from which the passenger is not scheduled to depart within 24 hours of arrival.
Originally Posted by 78.2
For the purpose of this rule "Stopover" means: A deliberate interruption of a journey at an intermediate point from which the passenger is scheduled to depart later than 24 hours after arrival. (Local time)