lacuna

Lacuna is a term meaning a gap or missing portion, from Latin lacuna meaning ditch or hollow. It is used across disciplines to denote a space, cavity, or interval where something is absent or has been lost. The general sense is preserved in both scholarly and everyday usage.

In biology and anatomy, lacuna (plural lacunae) denotes a small cavity within a tissue. In bone, osteocytes reside within bone lacunae and communicate via thin channels called canaliculi, forming the lacunar–canalicular system. Cartilage contains cartilage lacunae housing chondrocytes. The term also appears in dental and other tissues to describe similar spaces.

In manuscripts and paleography, a lacuna is a conspicuous gap in a text where content has been lost, damaged, or never copied. Textual criticism documents lacunae in manuscripts and inscriptions; editors may note lacunae when reconstructing the original wording.

In law and policy, a lacuna refers to an omission or gap in a statute, regulation, or system that leaves certain situations unaddressed. When a lacuna is identified, legal scholars may debate the need for new legislation or interpretation.

In medicine, the term appears in phrases such as lacunar infarct, referring to small, cavity-forming areas in the brain caused by occlusion of small penetrating arteries. While the term literally means “a small space,” its use highlights a discrete, hollow region or lesion.

In broader usage, lacuna can describe any gap in knowledge, culture, or memory, such as a historical lacuna in archives or a gap in a narrative.