"Pinch welds" refers to the raised edge or ridge on a vehicle's frame where the body panels are joined. These welds help hold the body panels together and provide strength and stability to the overall structure of the vehicle. Full definition
when you remove wheels, place them under the rocker panels or pinch weld seams so if the car falls, it won't fall on the ground. (mechanics.stackexchange.com)
It was installed under the door, not on the pinch weld of the car. (humblemechanic.com)
They will help prevent damage to the pinch welds on the car. (humblemechanic.com)