The term 'Head of Garlic' is a reference to the BULB of garlic, which is the part of the plant that is used for cooking and medicinal purposes. The BULB is made up of several cloves of garlic that are held together by a thin white skin. The BULB is the most commonly used part of the garlic plant and is usually harvested when the plant is mature. It can be used fresh or dried and has a strong flavor and aroma.