In engineering, redundancy is the duplication of critical components of a system with the intention of increasing reliability of the system. In safety-critical systems, such as fly-by-wire aircraft, some parts of the control system may be triplicated. An error in one component then may then be out-voted by the other two. See safety engineering.
In information theory, redundancy is the number of bits used to transmit a message minus the number of bits of actual information in the message. Data compression is a way to eliminate such redundancy.
In employment law, redundancy is the dismissal of an employee when his or her job becomes unnecessary. UK redundancy law allows three reasons for redundancy:
- Total cessation of the employer's business (whether permanently or temporarily)
- Cessation of business at the employee's workplace
- Reduction in the number of workers required to do a particular job.