The term 'Gadget Used on a Lemon' can be summarized as a Zester, which is a kitchen tool with a sharp blade used to remove the outer layer of citrus fruits such as lemons. It is typically made from stainless steel and has a handle for easy gripping. The zester is used to create thin strips of zest, which are the flavorful outermost layer of the fruit's skin. The zest can then be used to add flavor to dishes or drinks.