backup

名词 backup:

1. an accumulation caused by clogging or a stoppage
2. someone who takes the place of another (as when things get dangerous or difficult)
   同义词：stand-in, substitute, relief, reliever, backup man, fill-in
3. a subordinate musical part; provides background for more important parts
   同义词：accompaniment, musical accompaniment, support
4. (computer science) a copy of a file or directory on a separate storage device
   同义词：computer backup
5. the act of providing approval and support
   同义词：backing, championship, patronage

back.up

n.（名词）

A reserve or substitute.
改变或替代
Computer Science A copy of a program or file that is stored separately from the original.
【计算机科学】 备份：从原文中独立出来单独贮存的程序或文件的副本

Support or backing.
支援或支持
Music A background accompaniment, as for a performer.
【音乐】 伴奏：为一个演奏者配音伴奏
An overflow or accumulation caused by clogging or by a stoppage:
阻塞：由阻碍或停顿引起的泛滥或堆积：
例句：
a backup in the sink; a backup of traffic at the drawbridge.
下水道堵塞；吊桥上的交通阻塞

adj.（形容词）
Extra; standby:
额外的；替补的：
例句：
a backup pilot.
候补飞行员