backup

IPA: bˈækʌp

A reserve or substitute.
(computing) A copy of a file or record, stored separately from the original, that can be used to recover the original if it is destroyed or damaged.
An accumulation of material caused by a (partial) obstruction or (complete) blockage of the flow or movement of the material, or an accumulation of material that causes an overflow due to the flow being greater than the maximum possible flow.
(law enforcement) reinforcements
Any support or extra help.
(music) Accompaniment

(computing, nonstandard) Alternative form of back up [(idiomatic, intransitive) To move backwards, especially for a vehicle to do so.]

back up

IPA: bˈækˈʌp

(idiomatic, intransitive) To move backwards, especially for a vehicle to do so.
(idiomatic, transitive) To move a vehicle backwards.
(idiomatic, intransitive) To undo one's actions.
(idiomatic, intransitive) To reconsider one's thoughts.
(idiomatic, computing, transitive) To copy (data) so that it can be restored if the main copy is lost.
(idiomatic, transitive) To provide support or the promise of support to.
(idiomatic, intransitive, cricket) For the non-striker to take a few steps down the pitch, in preparation to taking a run, just as the bowler bowls the ball.
(idiomatic, intransitive, cricket) For a fielder to position himself behind the wicket (relative to a team-mate who is throwing the ball at the wicket) so as to stop the ball, and prevent overthrows.
(idiomatic, intransitive, of a blockage) To halt the flow or movement of something.
(idiomatic, intransitive, informal) To fill up because of a backlog.

IPA: bˈækʌp

And try to have some sort of long-term back-up plan.
I have a small bank account in Mexico for a back-up but never need it.
But I tend to be overly cautious too, and try to have at least 3 back-up plans!
But Renault has already kick-started a back-up ultra low cost car project in Chennai.
Fortunately, my wife, who joined me on this approximately 15-hour vacation, and I had a back-up plan.
I carry around my debit card with a smaller daily limit for regular use and keep the Visa debit card for credit card purchases, larger withdrawals, and a back-up card but don't usually carry it for safety reasons. gpkisner
The new site lacked sufficient customer call back-up, and when Ad Age reported that customers were spending 19% more on the site, the company cheered, only to learn that really meant people were spending that time in frustration.
Two girls are threatening each other with knives, encouraged by a gang of fellow-teenagers: before police back-up arrives, Lynn successfully deals with the immediate threat, until someone in the crowd fires a gun - Lynn is injured and one of the girls is killed.