What is a USB 'header' (and how is it different from a port)?

With the prevalence of USB devices, it might be easy to mix up USB headers and ports, but there is a key difference between ...
How-To Geek on MSN

3 USB-C powered gadgets I never knew I needed

USB-C is finally making its way into everything, and I'm all for it. It's no longer just a cable for phones and laptops.