The whole topic of color management can get pretty dry and technical, but stick with it because there’s information here that’s useful and puts lots of other things in context.
RGB
RGB stands for red, green and blue, the three color ‘channels’ that go to make up all the colors in a digital image. It comes in two varieties – sRGB is a ‘universal’ RGB that can be used and displayed by any device, whereas Adobe RGB is a more specialised alternative for pros.