Flex-fuel is a term primarily used in the automotive industry to refer to vehicles that can run on a combination of traditional gasoline and biofuels like ethanol and methanol. Some common synonyms for the term Flex-fuel include E85, FFV (Flexible Fuel Vehicle), Dual-fuel, and Bi-fuel. These terms are used interchangeably to refer to vehicles that are designed to operate on multiple fuel types, allowing car owners to make a sustainable and environmentally conscious decision, and save on fuel costs at the same time. While these terms may sound different, they all refer to the same technology that is becoming increasingly popular among car buyers who are concerned about their carbon footprint.