What term describes a small hollow socket for a tooth or an air sac in the lung?

The term that accurately describes a small hollow socket for a tooth or an air sac in the lung is "alveolus." In the context of dentistry, the alveolus refers to the bony socket that holds the roots of the teeth. Each tooth is anchored in its respective alveolus, providing stability and support. In the respiratory system, alveoli are tiny air sacs in the lungs where gas exchange occurs, allowing oxygen to enter the blood and carbon dioxide to be expelled from the body. This dual meaning underscores the importance of alveoli in both dental anatomy and respiratory physiology.

The other terms do not relate to the specific definition provided. Anemia refers to a deficiency of red blood cells or hemoglobin in the blood, which is unrelated to the concepts of sockets or air sacs. An aneurysm is an abnormal bulging in the wall of a blood vessel, and anesthesia pertains to the state of controlled, temporary loss of sensation or awareness, typically used during medical procedures. None of these terms embody the characteristics of a socket for a tooth or an air sac in the lung as effectively as "alveolus" does.