redundancy

The state of being redundant.

A superfluity; something redundant or excessive; a needless repetition in language.

[…] the fulneſs of the creature is limited, it ariſeth juſt to ſuch a degree and proportion, but Gods fulneſs is infinite, as it hath its Reſplendency, ſo its Redundancy, it knows neither bounds nor bottom.

A duplication of components or circuits to provide survival of the total system in case of failure of single components.

2006, Lauren Bean, Richard E. Friedman, Chapter 5: School Safety in the Twenty First Century: Adapting to New Security Challenges Post-9/11, James J. F. Forest (editor), Homeland Security: Protecting America′s Targets, Volume 2: Public Spaces and Social Institutions, page 108, Staff redundancy is needed in the event that a supervisor and key unit supervisors are not present or unable to act in an emergency.

Duplication of parts of a message to guard against transmission errors.

The state of being unemployed because one's job is no longer necessary; the dismissal of such an employee; a layoff.

1981, New Zealand House of Representatives. Parliamentary Debates, Volume 442, page 4212, Has he received any representation from Air New Zealand management about redundancy proposals for Air New Zealand staff; and, if so, do these proposals include redundancy agreements?

1983, UK House of Commons, Papers by Command, Volume 40, page lvi, The potential savings did not take into account once-and-for-all staff redundancy costs of £16.5 million and unspecified costs involved in increasing stock levels […] .