Meanings of backstair in English

We went clapping up a clean stone backstair, and then into a back passage cheerfully decorated with ragged light-green Kidderminster, and issued upon

And Miss Verity descended the backstairs again.

His reading is principally Memoirs, which I think I have heard you call 'The backstairs of history.'

"He wasn't groom of the backstairs to England's queen for nothing."

Had she been a second-hand clothes dealer, a frequenter of the backstairs of great houses, or had she been merely a courtesan?

Everybody pays a penalty for peeping through keyholes, and the keyhole and the backstairs are essential parts of the method of the modern biographers.

There's a board on the backstairs that squeaks, and I heard it plain, while you was still at me, hammer and tongs, Lydia answered.