A car jack is a mechanical device used to lift a vehicle off the ground, allowing for maintenance or tire changes. It typically consists of a sturdy frame and a lifting mechanism, which can be operated manually or hydraulically. Car jacks come in various types, including floor jacks, scissor jacks, and bottle jacks, each designed for specific lifting needs. To use a car jack safely, it is essential to place it on a stable surface and follow the manufacturer's instructions. Always use jack stands for added safety once the vehicle is lifted, as relying solely on the jack can be dangerous.