Bacteria, fermenting alcohol (like wine) or cider or dates, oranges, bananas, even rice, make the by-product we know as vinegar. In fact, vinegar can come from any food that can ferment into alcohol. Exposing this alcohol to air eventually turns it into vinegar.
Vinegar is used to make salad dressings, mayonnaise, mustard, pickles, and to preserve fruits and vegetables. It is used in many marinades for meat and poultry and beans because it adds such a distinct flavor. Vinegar is mostly water but it does contain a tiny amount of carbohydrates. It doesn't add any fat, protein, vitamins, or minerals to the food it is used in.
Besides for food, vinegar is also used to treat wounds, keep insect bites from itching and swelling, to soothe sunburns, and to relieve headaches. Some people use it to freshen their laundry, also. Vinegar can be stored at room temperature for a very, very, very long time. If your vinegar starts to have a cloudy appearance, don't worry about it. It is still good. The cloudy mass is called a mother of vinegar and it is what helped to make the vinegar in the first place.