A USB hub is a device that expands a single Universal Serial Bus (USB) port into several so that there are more ports available to connect devices to a host system, similar to a power strip. All devices connected through a USB hub share the bandwidth available to that hub.
A four-port "long cable" "external box" USB hub
A four-port "compact design" USB hub: upstream and downstream ports shown
A "star" "short cable" external USB with the plastic casing removed
USB multiport adapter: USB-C alt mode cable, USB PD (USB-C) port, a HDMI port, three USB 3.2 ports, an Ethernet port.
Universal Serial Bus (USB) is an industry standard that allows data exchange and delivery of power between many types of electronics. It specifies its architecture, in particular its physical interface, and communication protocols for data transfer and power delivery to and from hosts, such as personal computers, to and from peripheral devices, e.g. displays, keyboards, and mass storage devices, and to and from intermediate hubs, which multiply the number of a host's ports.
Various legacy USB and related connectors (left to right): USB Micro-B plug, proprietary UC-E6 plug, USB Mini-B plug, Standard-A-like receptacle (non-compliant), Standard-A plug, Standard-B plug. Shown with a centimeter ruler.
USB logo on the head of a standard Type-A (Standard-A) plug
A USB 2.0 PCI expansion card
USB 3.2 Gen 1(x1), Standard-A connectors labelled as USB 3.1 Gen 1 – originally simply named USB 3.0 and marketed as SuperSpeed USB (by USB 3.0 specification) and later named as USB 3.2 Gen 1x1 and marketed as SuperSpeed USB 5Gbps by the USB 3.2 specification
