USB C is an open specification used by many mobile devices like phones, tablets and laptops. It is an open specification because it is not proprietary to any single company and instead can be used in products by any vendor. A key feature is USB-C is that it is reversible while previous USB versions were not.
USB-C, or USB Type-C, is a connector (not a protocol) that supersedes previous USB connectors and can carry audio, video and other data, e.g., to drive multiple displays, to store a backup to an external drive. It can also provide and receive power, such as powering a laptop or a mobile phone. It is applied not only by USB technology, but also by other protocols, including Thunderbolt, PCIe, HDMI, DisplayPort, and others. It is extensible to support future standards.
USB-C attempts to be reversible and has 24 pins. The designation "C" is to distinguish it from the various former USB connectors it replaced, all termed either Type-A or Type-B. Whereas earlier every USB cable had a host end A and a peripheral device end B, USB-C replaces both; a USB-C cable connects either way, and for older equipment a legacy cable has a Type-C plug at one end and either a Type-A (host) or a Type-B (peripheral device) plug at the other. The designation "C" refers only to the connector's physical configuration, or form factor, not to be confused with the connector's specific capabilities, such as Thunderbolt 3, DisplayPort 2.0, or USB 3.2 Gen 2x2. Based on the supported protocols by both devices, host and peripheral device, a USB-C connection normally provides (much) higher signaling and therefore data rates than the superseded connectors.
The USB Type-C Specification 1.0 was published by the USB Implementers Forum (USB-IF) and was finalized in August 2014. It was developed at roughly the same time as the USB