Origins
The word 'diabetes' names a group of metabolic diseases characterized by elevated blood glucose levels due to defects in insulin production, insulin action, or both. The most common forms are Type 1 (autoimmune destruction of insulin-producing cells) and Type 2 (insulin resistance). The word entered English medical vocabulary in the 1560s from Latin 'diabētēs,' which was taken directly from the Greek.
Greek 'diabētēs' (διαβήτης) literally means 'one that passes through' or 'a siphon.' It derives from the verb 'diabainein' (διαβαίνειν), meaning 'to pass through, to go across, to stride over,' a compound of 'dia-' (through, across) and 'bainein' (to go, to walk, to step). The name captures the most conspicuous symptom of untreated diabetes: polyuria, or the production of excessive quantities of urine, as if fluid were being siphoned through the body without being retained.
The physician credited with applying this word to the disease is Aretaeus of Cappadocia, a Greek physician practicing in Rome or Alexandria in the second century CE. His clinical description is vivid and memorable: he wrote that diabetes was 'a melting down of the flesh and limbs into urine,' and that 'life is short, unpleasant, and painful; thirst is unquenchable.' He chose 'diabētēs' specifically for the image of a siphon — liquid flowing in at one end and out the other without pause.
Latin Roots
The qualifier 'mellitus' (Latin for 'honey-sweet') was added much later by Thomas Willis in 1675 to distinguish the sugar-related form (diabetes mellitus) from 'diabetes insipidus' (a different condition involving excessive urination but without elevated blood sugar, from Latin 'insipidus,' tasteless). The diagnostic method behind these names was startlingly direct: physicians tasted the patient's urine. Sweet urine indicated diabetes mellitus; tasteless urine indicated diabetes insipidus. This practice continued into the eighteenth century.
The Greek verb 'bainein' (to go) from which 'diabetes' is partly formed traces to PIE *gʷem- (to go, to come), a root with wide reflexes. English 'come' descends from this same root through Germanic. Greek 'basis' (a stepping, a base) also derives from 'bainein,' as does 'acrobat' (from 'akrobatos,' walking on tiptoe — 'akros' meaning high + 'bainein'). The military term 'anabasis' (a march up-country, famously Xenophon's title) combines 'ana-' (up) with 'basis.'
Diabetes has been recognized as a disease for thousands of years. The Egyptian Ebers Papyrus (c. 1550 BCE) describes a condition of excessive urination, and ancient Indian physicians (Sushruta and Charaka, c. 600 BCE) identified what they called 'madhumeha' — 'honey urine' — noting that ants were attracted to the urine of affected patients. The discovery of insulin by Frederick Banting and Charles Best in 1921 transformed diabetes from a death sentence into a manageable condition.