From WordNet (r) 2.0 (August 2003) [wn]:
backup
n 1: an accumulation caused by clogging or a stoppage; "a traffic
backup on the main street"; "he discovered a backup in
the toilet"
2: 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" [syn: stand-in, substitute, relief,
reliever, backup man, fill-in]
3: a subordinate musical part; provides background for more
important parts [syn: accompaniment, {musical
accompaniment}, support]
4: (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" [syn:
computer backup]
5: the act of providing approval and support; "his vigorous
backing of the conservatives got him in trouble with
progressives" [syn: backing, championship,
patronage]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
backup \back"up\, n.
1. anything kept in reserve to serve as a substitute in case
of failure or unavailability of the normal or primary
object; -- used for devices, plans, people, etc. Also used
attributively; as, there was no backup for the electrical
supply; a backup motor; a backup generator.
[PJC]
2. (Music) a musician or group of musicians accompanying a
soloist, whether vocalists or instrumentalists.
Syn: accompaniment. [PJC]
3. a person or group of persons serving as reinforcement for
another or others; as, the policeman called for backup
when he was fired on.
[PJC]
4. an accumulation, overflow, or reverse flow (in traffic or
a liquid flow system) caused by a stoppage or other
malfunction.
[PJC]
5. (Computers) A copy of a program or data from a computer
onto a data-storage medium, usually one that may be
removed to safe storage at a distance from the computer;
it is used to preserve data for use in the contingency
that the original data on the computer may be lost or
become unusable. A backup that is removed from the
building housing the computer system (to provide
protection against loss of data in a disastrous event such
as a fire) is called off-site backup. Also used
attributively; as, backup copy.
[PJC]
6. (Computers) The act or process of creating a backup[5];
as, they performed a full system backup every weekend.
[PJC] Backward
From The Free On-line Dictionary of Computing (19 Sep 2003) [foldoc]:
backup
<operating system> (Sometimes "back up" when used as a verb) A
spare copy of a file, file system or other resource for use in
the event of failure or loss of the original.
The term is most commonly used to refer to a copy of all the
files on a computer's disks which is made periodically and
kept on magnetic tape or other removable medium (also called
a "dump").
This essential precaution is neglected by most new computer
users until the first time they experience a disk crash or
accidentally delete the only copy of the file they have been
working on for the last six months.
Ideally the backup copies should be kept at a different site
or in a fire safe since, though your hardware may be insured
against fire, the data on it is almost certainly neither
insured nor easily replaced.
See also differential backup, incremental backup, {full
backup}. Compare archive.
(2003-06-22)