Help wanted with broken ac

What do you call "reading full"? I mean no offense at all when I say this, but that sounds like an unformed phrase when discussing A/C. Can you get more specific?
Sorry for lack of context/info and knowledge haha, I’m 18 and this is my first “project” car. I assumed the ac would work the same as my daily driver but after reading other comments I now realize that it’s probably a different concept. I had bought a recharge kit and put a gauge that it came with on my ac and it read that the refrigerant was full