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Phrase(s): back someone up
to provide someone with help in reserve; to support someone. • Don’t worry. I will back you up when you need me. • Will you please back up Nancy over the weekend?, Phrase(s): back up (to someone or something)
to move backwards to someone or something. (See also back someone or something up to someone or something.) • The bus backed up to the end of the parking space., Phrase(s): back something up
1. Lit. to drive a car backwards. • Will you back your car up a little? • I will back up the car. 2. Lit. to cause objects to obstruct a pathway or channel and cause a slowdown in the flow. • The wreck backed the cars up for a long way. • Some dead branches and leaves backed the sewer up. 3. Fig. to give additional support or evidence about something. (To support or strengthen the facts.) • My story of the crime will back your story up. • That backs up my story, all right., Phrase(s): back up (to something)
to go back to something said in a conversation. • Wait—back up a little. What did you say that phone number was? • Let’s back up to what you just said and go over that point again., Phrase(s): back up
1. Lit. [for objects] to obstruct and accumulate in a pathway or channel. • Something clogged the sewer and it backed up. 2. Fig. to refuse to go through with something; to back out (of something). • Fred backed up at the last minute, leaving me to do the job alone.
McGrawhill's American Idioms And Phrasal Verbs
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Move or drive a vehicle backward, as in He told her to back up into the garage. [First half of 1800s] 1. Bring or come to a standstill, as in The water had backed up in the drains, or The accident had backed up traffic for miles. [First half of 1800s] 3. Support or strengthen, as in The photos were backed up with heavy cardboard so they couldn't be bent, or I'll back up that statement of yours. [Second half of 1700s] 4. Duplicate a file or program so that the original is not lost. For example, Every computer manual warns you to back up your work frequently 2. in case of a power outage or computer failure. [Second half of 1900s]
American Heritage Idioms