What exactly does the spec “PCIe x16 slot ” mean?

Modifying a x8 PCIE slot to take a x16 GPU! I fixed my pciex16 slot configuration * The PCIEX16 slot can only support a graphics card or an NVMe SSD If only one graphics card is to be installed, be sure to install it in the PCIEX16 slot pciex16 slot A PCIe slot that supports an FHFL PCIe card is backward compatible with an FHHL or HHHL PCIe card · A PCIe slot that supports a PCIe x16 card is

pop slot free Modifying a x8 PCIE slot to take a x16 GPU! I fixed my servers jank 24 Thread PowerEdge