backup /ˈbækˌʌp/ n. [c] 1. 帮助；援助；支持：military backup军事援助 2. 替代物；备用品；备份：a backup disk备份磁盘 Have you kept a backup of this file? 你把这文件备份了吗? The hospital has a backup generator in case there is a power failure.医院有备用发电机以防停电。