A CUDA core is a processing unit found in NVIDIA's graphics processing units (GPUs) that enables parallel computing. It is designed to handle multiple tasks simultaneously, making it ideal for applications that require high-performance computing, such as video rendering, scientific simulations, and machine learning. Each CUDA core can execute a thread, which is a sequence of instructions. By utilizing thousands of CUDA cores, a GPU can perform complex calculations much faster than a traditional CPU. This architecture allows developers to harness the power of the GPU for general-purpose computing, often referred to as GPGPU (General-Purpose computing on Graphics Processing Units).