Air-cooled is a term used to describe a mechanical device that uses air to cool its components. It is commonly used to define engines, generators, and electronic devices. Antonyms for air-cooled would be water-cooled or liquid-cooled. In a water-cooled system, a circulating liquid, usually water mixed with antifreeze, is used to absorb heat and transfer it away from the device. This method is commonly found in cars, computer processors, and refrigerators. Liquid-cooled systems are similar, but they use different liquids like oils or refrigerants. They are commonly found in industrial machinery and high-performance cars. Both water-cooling and liquid-cooling provide superior cooling capabilities compared to air-cooling, but they also require more complex systems and additional maintenance.