1. (

• backup

) an accumulation caused by clogging or a stoppage; "a traffic backup on the main street"; "he discovered a backup in the toilet" ;

2. (

• stand-in ,
• substitute ,
• relief ,
• reliever ,
• backup ,
• backup_man ,
• fill-in

) someone who takes the place of another (as when things get dangerous or difficult); "the star had a stand-in for dangerous scenes"; "we need extra employees for summer fill-ins" ;

3. (

• accompaniment ,
• musical_accompaniment ,
• backup ,
• support ,

) a musical part (vocal or instrumental) that supports or provides background for other musical parts ;

4. (

• backup ,
• computer_backup

) (computer science) a copy of a file or directory on a separate storage device; "he made a backup in case the original was accidentally damaged or erased" ;

5. (

• backing ,
• backup ,
• championship ,
• patronage

) the act of providing approval and support; "his vigorous backing of the conservatives got him in trouble with progressives" ;