(electronics) a system design that duplicates components to provide alternatives in case one component fails WordNet 3.0 & Open English WordNet

In engineering and systems theory, redundancy is the intentional duplication of critical components or functions of a system with the goal of increasing reliability of the system, usually in the form of a backup or fail-safe, or to improve actual system performance, such as in the case of GNSS receivers, or multi-threaded computer processing. Wikipedia

The duplication of critical components or functions of a system with the intention of increasing reliability Wikipedia Disambiguation

Use of a number of critical components for securing one or more functions of a system with the intention of increasing its reliability, usually in the form of a backup or fail-safe design Wikidata

Duplication of components or circuits to provide survival of the total system in case of failure of single components. OmegaWiki