Definition
Backup refers to a copy of data or files made for safekeeping, or to additional support or resources available if needed. It serves as a safeguard against loss or failure. Think of it as a plan B. It can also mean providing assistance or support to someone. A 'backup' contrasts with relying solely on a single source or plan. It's like having a spare tire in your car; you hope you don't need it, but it's essential if you do.