The human brain is divided into two hemispheres, left and right. In between is the corpus callosum, which facilitates communication between the two hemispheres.
The hemispheres tend to be dominant for different types of processing. The right brain is usually stronger in spatial thinking, face recognition, visual imagery, music and holistic/intuitive thinking. The left brain is usually stronger in language, math, logic and sequencing. However, there are variations among people. For example, accomplished musicians tend to process music more in their left hemisphere, whereas an amateur tends to use the right brain more. Conversely, mathematicians and high-level chess players tend to use their right brains far more than a novice would.
As we function in the world, we are constantly integrating information from both sides of the brain. We recognize a face using the right side of the brain, but we know the name of the person and other information about them using the left. When we move, we integrate gross motor (right) and fine motor (left) abilities.