backup
UK: ˈbækʌp | US: ˈbækˌʌp
n. 1. A copy of data stored separately for security or recovery purposes.
n. 2. Support or reinforcement provided to a person or group.
vt. 3. To make a duplicate copy of data as a safeguard.
The word "backup" combines "back," derived from Old English bæc (meaning "rear" or "support"), and "up," from Old English upp (indicating completion or emphasis). Originally used in the 18th century to describe military reserves ("backing up" troops), it evolved in the mid-20th century to denote data duplication in computing, reflecting the idea of "support" through redundancy.
Always create a backup of important files to avoid data loss.
The team called for backup when the project became overwhelming.
She backed up her phone photos to the cloud.
The police arrived as backup during the emergency.
The generator serves as a backup power source.