A core is nothing but a physical processing core. In the past, CPUs didn't contain multiple cores. However, they only had a single core managing the processing. After technological development, we got to see dual and quad-core CPUs. It was like having 2 or 4 CPUs operating on a single chip. In the 20th century, multi-core processors were standard. What's more, multi-core processors are quite beneficial when you perform gaming, video rendering, or live-streaming activities.