a door at the rear of a house, building, etc.: Fans were waiting by the backdoor of the theater, hoping to catch a glimpse of the band.
a secret, furtive, or illicit manner or means: The business has a backdoor through which the board of directors can access slush fund money.
an indirect manner or means: Marriage counseling was a kind of backdoor into therapy, where I finally faced my dysfunctional relationship with my mother.
Computers. a secret access point or undocumented vulnerability in a software program, hardware component, or digital network, sometimes intentionally maintained as for remote developer access, but also sometimes created or exploited for unauthorized access by hackers: If half of all devices have disclosed backdoors, cybersecurity experts must assume that the number of devices affected by undisclosed or malicious backdoors is much higher.
Slang: Usually Vulgar. anus.
indirect: The immigration reform bill included backdoor amnesty for employed undocumented residents.
Computers. relating to, using, or noting an indirect access point into a network, computer, or program: Hackers used a Trojan horse to establish backdoor access to the mainframe.
Slang: Vulgar. anal (def. 1).
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
How to use backdoor in a sentence
Walker makes it to his back door and gingerly steps into the inky night.
He opened the back door of the Humvee, where Mace was trying ease himself out.
But when he returned home, he would always enter through the back door.‘I Just Thought He Was Odd’: Neighbors of the Cleveland Kidnapper on What They Saw | Christine Pelisek | May 8, 2013 | THE DAILY BEAST
Since 2008, when Cyprus joined the euro zone, Russian big shots have been using the country as a back door into Europe.Why Europe’s Response to the Cyprus Crisis Has Been Ineffectual | Daniel Gross | March 24, 2013 | THE DAILY BEAST
Witnesses said they saw a man drop a bag near the back door of the bus and flee moments before the explosion.
Ned reached home about breakfast time, and "fetched up" at the back door, with a decidedly guilty countenance.The Book of Anecdotes and Budget of Fun; | Various
He saw that the back door of the armored truck was opening and another guard was getting out.
When Mrs. Foley and the baby arrived home there stood upon the platform at the back door of the house a most amazing figure.The Campfire Girls of Roselawn | Margaret Penrose
The Czar returned the visit with the same precautions, and was admitted into Kensington House by a back door.The History of England from the Accession of James II. | Thomas Babington Macaulay
So when the servants of the house heard the cry in the orchard, they rushed in by the back door, to see what was the matter.The Bible, Douay-Rheims Version | Various
British Dictionary definitions for back door
a door at the rear or side of a building
a means of entry to a job, position, etc, that is secret, underhand, or obtained through influence
(as modifier): a backdoor way of making firms pay more
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Other Idioms and Phrases with backdoor
An entry at the rear of a building, as in Deliveries are supposed to be made at the back door only. [First half of 1500s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.