Contiguous

Contiguous describes things that touch or are in contact along a boundary, or that form an unbroken sequence. In everyday usage it often means adjacent or neighboring without gaps. The term is used across disciplines with a common emphasis on connectedness. It derives from Latin contiguus, from contingere, to touch.

In geography, contiguous commonly refers to items that share a border or are part of a single landmass. The contiguous United States denotes the 48 adjoining states on the North American mainland, excluding Alaska and Hawaii.

In mathematics and topology, a set is called contiguous if it is connected, with no holes or separations. In the real line, intervals such as [a,b] are contiguous, while a union of disjoint intervals is not. A contiguous sequence or substring in computer science and combinatorics consists of elements with consecutive indices and no gaps; similarly, a contiguous block in an array or string is a consecutive run.

In computing, contiguous memory allocation arranges data in adjacent memory addresses. This layout supports fast indexing and spatial locality but can suffer from fragmentation and difficulties growing allocations.

Overall, contiguous emphasizes unbroken adjacency or uninterrupted extent, whether describing physical borders, mathematical sets, or data structures.