Is there any difference between a diuretic and dehydration?

Diuretics : If used too long or overprescribed can sometimes cause dehydration.

Yes: A diuretic is a material that makes you pee off more body water than you would otherwise. Dehydration is when you have lost body water content through one of several means. Sweat, excess urination, diarrhea, exhaled lung moisture, etc. Dehydration is a clinical term usually applied to an acute drop in body weight by at least 5% & since the body is 60-70% water it reflects water loss.