Final answer:
In haircutting, the area below the parietal/crest is referred to as the occipital, which is named after the occipital bone and lobes of the brain located just below the parietal bones and lobes.
Step-by-step explanation:
In haircutting, the area below the parietal/crest is referred to as the occipital. This region correlates with the occipital bone which forms the lower back part of the skull, just beneath the parietal bones.
The occipital lobes, located below the parietal lobes, contribute to the shape of this area of the head. The occipital lobes are dedicated almost solely to vision and are seated at the back of the head, forming the base of the cranium just above the neck. When discussing the area related to haircutting, the term 'occipital' refers to the part of the head that starts just below the parietal ridge and encompasses the back of the head where hair is typically shorter, particularly in traditional men's cuts. This should not be confused with the nape, which is even lower, at the back of the neck.