back stairs

US: (bak′stârz′)

WordReference Random House Unabridged Dictionary of American English © 2025

back′ stairs′, 

1. stairs at the back of a house, as for use by servants.
2. a means of intrigue.
• 1620–30

back•stairs  (bak′stârz′), adj. 

1. associated or originating with household servants.
2. secret, underhanded, or scandalous:
   backstairs gossip.

Also, back′stair′. 

• adjective, adjectival use of back stairs 1635–45