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 ...
Ars Technica

Can you attach multiple USB-C plugs to a single motherboard header?

This one is a powered hub (using a SATA connector) going to a standard USB 3.0 header. My assumption is that it functions like a 4-port hub connected to a single set of pins coming from the header (so ...
PC World

Every I/O connector for your desktop PC’s front panel, explained

I’m a big proponent of DIY PC building and I tend to describe it as “relatively straightforward.” For the most part, everything just plugs in where it should. But there is one aspect of putting ...