Interdigit

Interdigit is a verb meaning to interlock or fit together by means of interlacing, fingerlike projections. It derives from inter- and digit (finger) and is related to the noun interdigitation and the adjective interdigitated. The term is used across disciplines to describe a pattern or interface where structures touch or mesh like the fingers of two hands.

In anatomy and histology, interdigitations describe interlocking tissue processes that increase contact area and adhesion between neighboring tissues. Examples include the interdigitations at the dermal–epidermal junction and other regions where neighboring surfaces extend fingerlike projections to stabilize the connection or to enhance exchange.

In engineering and electronics, interdigitate or interdigitate is used to describe two comb-like structures that interlock. This pattern yields interdigitated electrodes (IDEs), consisting of alternating fingerlike electrodes with a small gap between them. IDEs are common in sensors, microfluidic devices, capacitive systems, and impedance measurements because the configuration provides large surface area and strong field interactions in a compact footprint.

The term is typically used with its related forms: interdigitate (verb), interdigitated (adjective), and interdigitation (noun). Usage depends on context: biological contexts emphasize tissue morphology; engineering contexts emphasize patterned interfaces and fabrication geometries. Interdigitation generally increases contact area, improves mechanical stability, or enhances interfacial phenomena between adjoining structures.