back-up
n
1 [U] support; reserve 支持; 支援; 後备
The police had military back-up. 警方有军队作後盾.
[attrib 作定语]
back-up services 善後服务
the back-up team of a racing driver 赛车手的後勤队.
2 [U, C] (computing 计) (making a) copy of a file, program, etc for use in case the original is lost or damaged (制作)(文件、程序等的)复制件(以备原件丢失或损坏时使用)
[attrib 作定语]
a back-up disc 复制件磁盘.