Earlier today the etymology of the Japanese word for "diabetes" came up.
In Japanese diabetes is 糖尿病 [to:ɲo:bjo:],
literally "sugar urine disease". To my interlocutor, this was mysterious.
It actually makes a lot of sense. Diabetes is a disease in which glucose in the
blood stream is unable to enter the cells that need it.
As a result, the glucose is not metabolized and a great deal is excreted in the
urine. The urine of diabetics is therefore sweet. At one time, tasting the patient's
urine was part of a European doctor's diagnostic toolkit.
[Update: I am told by a younger Cantonese speaker that 糖尿病 is now the more common term in Cantonese. I'm guessing that this is a result of Mandarin influence.]
The sweetness of the urine of diabetics is also the explanation for the full name for diabetes in English. There are actually two quite different conditions that go by the name diabetes. The more familiar one is diabetes mellitus, where mellitus is Latin for "honeyed". The other is diabetes insipidus, "tasteless diabetes", which refers to the weak taste of the urine.