There are many types of USB (Universal Serial Bus). The picture below displays most of them. The most common, which we are all familiar with, is Type-A. This is a large port.
One of the newest is Type-C. This can be inserted into a port either way (thank goodness!). The MacBook was the first computer to use this type. It is about 1/3 the size of Type-A.
There are also different versions of the USB. USB started with 1.0, worked its way up to 2.0, and is now on 3.0. USB 3.0 allows for a faster speed of transfer.
Soon, devices everywhere will be using Type-C (which has the capability to both charge and connect your device to another device).