an adviser to the court on some matter of law who is not a party to the case; usually someone who wants to influence the outcome of a lawsuit involving matters of wide public interest
(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"
an accumulation caused by clogging or a stoppage; "a traffic backup on the main street"; "he discovered a backup in the toilet"