<p><strong>Noun</strong></p><ul><li>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.</li><li>a secret, furtive, or illicit manner or means: The business has a backdoor through which the board of directors can access slush fund money.</li><li>an indirect manner or means: Marriage counseling was a kind of backdoor into therapy, where I finally faced my dysfunctional relationship with my mother.</li><li>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.</li><li>Slang: Usually Vulgar. anus.</li></ul><p><strong>Adjective</strong></p><ul><li>secret; furtive; illicit: Special interests pushed through a backdoor contract before the bidding period had expired.</li><li>indirect: The immigration reform bill included backdoor amnesty for employed undocumented residents.</li><li>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.</li><li>Slang: Vulgar. anal.</li></ul>