From Longman Dictionary of Contemporary Englishback doorˌback ˈdoor noun [countable] 1 DHHTBBa door at the back or side of a building2 → get in through the back door
Examples from the Corpus
back door• The job can be a back door into the bank's training program.• Sills testified he heard some one banging on his back door and he found the three brothers had let themselves into the kitchen.• She said in the interview that she refused to open the back door when she heard him knock.• Preston opened the back door and stared out into the garden.• After midnight we tiptoed down the hallway and out the back door, without anybody seeing us.• But as she reached the back door, the sound of a loud, angry voice stopped her in her tracks.• Then he walked her through the back door as he always did and stood by until she was in her car.• He came in through the back door on Lily's afternoon out. 