Definition
Universal Serial Bus (USB) is a standard for connecting peripherals, defined by the USB Implementers Forum (USB-IF), carrying both data and power between a host and external devices.
How it works
It uses a host–device architecture: devices attach to the host through standard connectors (such as Type-A and Type-C) and cables, and successive generations of the specification define data rates and power delivery, with host and device negotiating the capabilities they use.
Usage
USB handles the connection of keyboards, mice, external storage, printers and docking stations, as well as powering and charging phones and laptops.
Related and confusable terms
USB is a wired interface standard, unlike 5G cellular network technology—the former answers how one device attaches to another, while the latter answers how a device joins a wide-area network.