A standard type of USB connector, often found on phones, for connecting phones to chargers, computers, and other devices.
It is an industry-standard connector. Most phones use it for charging the battery, and also support one or more types of data connection via the port.
A single micro-USB port can support many types of connections depending on the phone settings and the device at the other end of the cable.
"Mass storage mode", MTP, and PTP modes allow a computer to access files and media stored on the phone.
See: Mass Storage mode
Data tethering over USB allows a computer to use a phone to connect to the Internet.
Some phones support MHL, which turns a micro-USB port into a video connector.
Some phones also support OTG, which lets a phone connect directly to accessories such as keyboards and memory sticks.
See: USB OTG
There is also a larger standard connector called Mini-USB, which is older and less popular on newer phones.