What is the meaning of Redundancy?

The state of being redundant

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

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

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.

surplusage inserted in a pleading which may be rejected by the court without impairing the validity of what remains.

Source: wiktionary.org