Piling in construction is the process of driving or boring piles into the ground to support a building. Piles are used to transfer the weight of the building to the ground.
It's the groundwork that anchors the building to the ground, including excavation, pouring concrete footings, and installing piles when necessary depending on soil conditions.
Fabrication in construction is the process of making parts for a building using raw materials. This involves designing, cutting, bending, assembling, and welding.