Ointment is a thick, soft stuff you rub into the skin, usually as medicine — for a burn, a rash, dry skin, or a cut the doctor wants to keep greasy and protected. It is thicker and oilier than a lotion, which is more watery, and often thicker than a cream. You buy it in a tube or a small tin at a pharmacy. There is an old saying, a fly in the ointment: one small thing that spoils something good. That fly is not sitting in your medicine; it is just a picture. The word looks like oint plus -ment. It came from French, from a Latin word meaning 'I rub oil or cream on someone.' English already had salve for the same kind of thing, and we still use salve a little, but ointment is the usual word now.