Computer compatibility means how well two or more devices work together. It's like putting together a puzzle. The pieces need to fit together or work together in order for everything to work and to not have any issues. For example, if you buy a new printer for your computer, you will want the printer to be compatible with the computer so that it can be used and printed correctly. Sometimes different versions of computers and software don't always work well together, so it's important to make sure that everything matches up and works together so that your computer runs properly.