A Geneva drive, also known as a Maltese cross mechanism, is a type of indexing mechanism that converts continuous rotation into discrete, precise movements. It consists of a rotating drive wheel with a pin that engages with a stationary geneva cross, which has multiple slots. As the drive wheel turns, the pin enters and exits the slots in the geneva cross, causing the driven component to move in distinct steps. This mechanism is commonly used in applications like rotary indexing tables and other devices that require precise intermittent motion.