DiabetesDiabetes is generally used synonymously to mean diabetes mellitus. However, the condition means literally "passing too much urine". It comes from the Greek word meaning to 'pass over' or 'cross over'. There are two forms of diabetes, namely diabetes mellitus and diabetes insipidus. By far the most common form of diabetes is diabetes mellitus. Increased amounts of urination are common to all forms of diabetes. Frequency (of urination), nocturia and thirst are other common symptoms. If a person with diabetes is found unconscious, a very likely cause is diabetic coma which is a medical emergency.