side door

plural side doors

1. A door that is not primarily used as an entrance or exit.

   Well, I generally come in at least fifteen minutes late, ah, I use the side door - that way Lumbergh can't see me, heh heh - and, uh, after that I just sorta space out for about an hour.

   1999, Mike Judge, Office Space (motion picture), spoken by Peter Gibbons (Ron Livingston)

   3 more examples

   He sneaked into the house quietly by a small side door. From there he slipped neatly into his sanctum. He flattered himself that his entrance had not been observed, but there he was mistaken. The watchful Tredwell let nothing escape him. He presented himself at the door.

   1925, Agatha Christie, The Secret of Chimneys

   "If she makes as much work after she comes as she has before, we might as well give up hope of ever gettin' any rest," sighed Miranda as she hung the dish towels on the barberry bushes at the side door.

   1903, Kate Douglas Wiggin, Rebecca of Sunnybrook Farm

   Once, this neo-Gothic landmark in Chelsea was the Church of the Holy Communion. . . . A decade later, it was Limelight, the nightclub-slash-den of depravity. . . . Today that fabled nightclub is a mall. . . . Entering by a side door, one young woman patently ignorant of the place’s tainted past, glanced around bewilderedly. “I thought that this was a house of God,” she murmured.

   2010 May 19, Ruth La Ferla, “Where God and the Devil Once Lived”, in The New York Times, archived from the original on 26 Jan 2021, retrieved 30 Jul 2011

2. figurativelyA method that bypasses the primary process.

   The USA won the home-and-home series with the Italians, entering the World Cup through a side door

   2012 January 17, Vicki Michaels, “After 'humbling' loss, U.S. women's soccer team is cautious”, in USA Today