noun, often attributive back·up \ -ˌəp \
Updated on: 13 Oct 2017

Definition of backup

1 a :one that serves as a substitute or support
  • I brought an extra pencil for backup.
  • a backup plan
b :musical accompaniment
  • The tunes include banjo and guitar backup.
c :additional personnel who provide assistance
  • The police officer called for backup.
2 :an accumulation caused by a stoppage in the flow
  • traffic backup
3 :a copy of computer data (such as a file or the contents of a hard drive)
  • I made a backup copy of the file.
; also :the act or an instance of making a backup

Examples of backup in a Sentence

  1. His role on the team is to be a backup to the regular quarterback.

  2. We have an extra radio as a backup in case this one doesn't work.

  3. We have an extra radio for backup.

  4. He provides backup for the regular quarterback.

  5. She sang backup on his CD.

Recent Examples of backup from the Web

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'backup.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of backup


backup Synonyms

back up


Definition of back up

intransitive verb
:to accumulate in a congested state
  • traffic backed up for miles
transitive verb
1 :to move into a position behind (a teammate) in order to assist on a play
2 :hold back 1
3 :to make a copy of (a computer file or data) to protect against accidental loss; also :to make copies of all the files on (a hard drive)

First Known Use of back up


Financial Definition of BACKUP

back up

What It Is

A back up is an increase in a security’s price, yield, or spread before issuance.

In other circles, back up means replacing a long-maturity security with a short-maturity security in order to capitalize on short-term interest rates that are higher than long-term interest rates.

How It Works

For example, let’s assume that Company XYZ wants to issue $100 million in 10-year bonds. The yields on bonds of similar quality and risk were about 5% when Company XYZ hired the underwriter to handle the bond issue, but since then the required yields have increased to 7%. This means Company XYZ has to issue the bonds at a bigger discount in order to keep the issue competitive, and thus it will obtain less cash from investors at the time of the sale.

This increase in the cost of issuing the securities is a back up.

Why It Matters

Back ups can be very detrimental to issuers, especially if they are relying on a very specific amount of money to come from the issue, and even more especially if the company’s success hinges on the reinvestment of those funds.

BACKUP Defined for English Language Learners



Definition of backup for English Language Learners

  • : a person or thing that can be used to replace or support another person or thing

  • : help or support provided by additional people or things

  • : a situation in which the flow of something (such as traffic) becomes blocked

BACKUP Defined for Kids


noun back·up \ ˈbak-ˌəp \

Definition of backup for Students

:a person who takes the place of or supports another
  • The guard called for a backup.

Seen and Heard

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to suppress quietly or indirectly

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