The brain is divided into a number of regions, but the area most humans refer to when they discuss the brain is the cerebral cortex, or cerebrum. This evolutionarily new region of the brain is present in all mammals, and is what allows complex thoughts rather than just automatic and unconscious processes.
Neuroscientists divide the cerebrum into four distinct lobes: parietal, frontal, temporal, and occipital. Because the brain is also divided into right and left hemispheres, each lobe has two separate regions. Thus the parietal lobe can be further divided into the left and right parietal lobes.