What exactly are half-head highlights?

Half-head highlights are only highlights on the top half portion of your hair, not the bottom. It's hard to have that natural looking highlight when lightening your hair. I got highlights a few weeks ago and my hair is black, at first it took some adjustment getting used to it, but after a couple weeks it looks alot more natural. Full highlights isn't as common anymore, most people just get the top half done, I guess its a personal/ financial choice, it usually is a little cheaper but I prefer the full. Hope it helps!