“What does protein in urine mean?”

It can be as simple as having a fever, exercising, or having a urinary tract infection. I could also mean this is afternoon urine, and many people will have some amount of protein in their urine that increases in the afternoon, which is called postural proteinuria. Then, it could be related to diabetes, which is poorly controlled, or high blood pressure, which is poorly controlled. Then we get into the more serious problems, such as nephrotic syndrome and what are called glomerulopathies. These require the expertise of a nephrologist to sort out.