Back door

Back door may refer to:

A door in the rear of a house or other building
Backdoor (computing), a hidden method for bypassing normal computer authentication systems
Back Door (jazz trio), a British jazz trio, drums sax and bass guitar, who played in the bar of the highest pub on the Yorkshire moors during the late 1970s. Their use of the bass guitar was ahead of its time
The Back Door (fiction), an 1897 work describing a fictional French and Russian invasion of Hong Kong
The Back Door (album), a 1992 album by American band Cherish the Ladies
Backdoor pilot, a method used to judge reaction to a potential new television series
In Jazz Music Theory, a Backdoor Progression is a characteristic harmonic device found in many Jazz Standards