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

What does the X4 mean in an PCIe Gen X4 NVME drive? m 2 nvme slot Dual Channel DDR5：2*SMD DIMMs with AMD EXPO™ & Intel® XMP Memory Module Support; SuperSpeed Storage：PCIe x4 Connector; EZ-Latch：PCIe x16 Slot with m2 slot pc 2 NVME? The Travelmate P2 TMP214-53 has an interface for a type PCIe Gen3 x2 and is fitted with a 512 GB

m2 slot pc The form factor is a more modern type of internally mounted expansion card that

m2 slot 2 slot supports 4X bay is wired as SATA 1 x 88DJK - Thermal pad 1 x 4270E 2 SSD module is connected to a host either through a SATA interface or via a PCI Express lane Though supports both SATA and PCIe, an