1、backup.名词 n.1.帮助；援助；支持 military backup军事援助2.替代物;备用品;支援人员, 后备, 后补, 助手 a backup singer for Stevie Wonder史蒂维·旺德的伴唱歌手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。

2、She once sang backup for Madonna.她曾经为麦当娜伴唱。

3、3.(流水受阻造成的)阻塞；泛滥；<美>(车辆等)拥塞4.<计>备份文件 a backup disk备份磁盘Have you kept a backup of this file？你把这文件备份了吗？We had no computer backup and had to rely on old paper files to reconstruct the records.我们没有计算机备份,只得靠落后的纸档案重做记录。