An STOVL is an acronym for Short Take Off and Vertical Landing. It is an ability of some aircraft like the F35B to take off from a short runway or take off verticalyy if it doesn't have a very heavy payload and land vertically. This is often accomplished on aircraft carriers through the use of "ski-jump" runways, instead of the conventional catapult system. STOVL use tends to allow aircraft to carry a larger payload as compared to during the VTOL use, while still only requiring a short runway.