Leg is the One segment of an itinerary.
Other definition:
leg is the on segment of a journey, normally referring to an air itinerary, such as the " outbound leg " or the " return leg "
Other definition:
Leg is one single flight portion of an itinerary.
Other definition:
Leg is the portion of a journey between two scheduled stops.
The Travel-Glossary: Everything about Travelling, Sightseeing and the World.