What is the technical name for the half moon at the base of the nail?

The correct term for the half moon at the base of the nail is "lunula." This anatomical feature is distinct because it represents the visible part of the nail matrix, where new nail cells originate. The lunula is typically lighter in color than the rest of the nail and varies in size and visibility from person to person. Understanding the structure of the nail, including the lunula, is essential for manicurists, as it can provide insight into the health of the nail and surrounding tissue.

The other terms listed refer to different components related to nails. For instance, "serena" does not correspond to any recognized anatomical term in relation to nails. "Hyponychium" refers to the area of skin under the free edge of the nail, forming a barrier to protect the nail bed. "Luna," while it sounds similar to lunula, does not define any part of the nail anatomy. Therefore, lunula is the appropriate and technically accurate name for the half moon shape seen at the base of the nail.