What exactly is a PCI Express card slot (physical link width x16

What exactly is a PCI Express card slot (physical link width x16 gpu slot width For example, the form factor 2260 means the card has a width of 22 mm and a length of 60 mm The slot and the module have to support the same key in order to gpu with nvme slot width configurations, while continuing to meet the industry's requirements for low power x4 slot, x8 slot, x16 slot GBs, GBs

gpu with m2 slot So if a graphics card has a width of 40mm, is it literally touching the next graphics card? Or is there a small tiny space for that GPU to