A GPU is a specialized type of hardware designed to handle complex calculations, especially those required to process images, graphics, or perform tasks in parallel. In AI, GPUs are essential because they can efficiently manage the large volumes of data and multiple calculations involved in training AI models. Unlike traditional CPUs, which process one or a few tasks at a time, GPUs can handle thousands of tasks simultaneously, making them ideal for tasks like image recognition, deep learning, and other data-intensive applications in AI.