Computer jargon means words to do with computers and surrounding topics. Knowing what these words mean can help people know more about computers. Most people use these words to discuss computer ideas, but some people use these words to impress others (also known as buzzwords).
ROM - read only memory. This is memory that does not get changed.
Hardware - the solid parts of a computer, like monitors, fans, CPU, etc.
CPU - central processing unit, another name for processor.
GHz - gigahertz. Used to describe the speed of a processor. Some processors are capable of doing more than one thing at once, as they have multiple "cores", so a bigger number is not necessarily better. The bigger the GHz number, the faster it runs and the more energy it uses.
USB - universal serial bus, a method used to plug computer tools into a machine.