Defn: The act of one who backslides; abandonment of faith or duty.
Our backslidings are many. Jer. xiv. 7.

BACKSTAFF
Back"staff`, n.

Defn: An instrument formerly used for taking the altitude of the heavenly bodies, but now superseded by the quadrant and sextant; — so called because the observer turned his back to the body observed.

BACK STAIRS
Back" stairs`.

Defn: Stairs in the back part of a house, as distinguished from the front stairs; hence, a private or indirect way.

BACKSTAIRS; BACKSTAIR
Back"stairs`, Back"stair`, a.

Defn: Private; indirect; secret; intriguing; as if finding access by
the back stairs.
A backstairs influence. Burke.
Female caprice and backstairs influence. Trevelyan.

BACKSTAY
Back"stay`, n. Etym: [Back, a. orn.+ stay.]

1. (Naut.)

Defn: A rope or stay extending from the masthead to the side of a ship, slanting a little aft, to assist the shrouds in supporting the mast. [ Often used in the plural.]