What does the X4 mean in an PCIe Gen X4 NVME drive?

PCIe bifurcation is no different to the definition dividing the PCIe slot in smaller chunksbranches Example, a PCIe x8 card slot

To connect them, you plug the PCIe card into the PCIe slot on the board Types of Slots and Cards There are 5 common types of PCIe slots and

pcie slot cover PCIe SSDs, on the other hand, connect directly to the PCIe slot and are smaller in size, enhancing speed and performance In 2008 PCIe SSDs

pcie 4 nvme in pcie 3 slot PCI Express was introduced in 2002 as Third Generation IO , and by the mid-2000s, motherboards had at least one PCIe slot for graphics PCIe