Focus. It has many definitions. In science, it is the point at which rays of light, heat, or sound meet after being reflected. In geology, it is the place inside the Earth's crust where an earthquake originates. For engineers working in machine vision, the camera definition is most likely familiar, and it is a combination of lens aperture and light.
When applied to the human brain, focus is defined as a center of activity, attraction, or attention, or a point of concentration.