Defn: An instrument which, in conjunction with another making an absolute disposition, constitutes a trust.

BACKBONE
Back"bone", n. Etym: [2d back,n.+ bone. ]

1. The column of bones in the back which sustains and gives firmness to the frame; the spine; the vertebral or spinal column.

2. Anything like , or serving the purpose of, a backbone. The lofty mountains on the north side compose the granitic axis, or backbone of the country. Darwin. We have now come to the backbone of our subject. Earle.

3. Firmness; moral principle; steadfastness. Shelley's thought never had any backbone. Shairp. To the backbone, through and through; thoroughly; entirely. "Staunch to the backbone." Lord Lytton.

BACKBONED
Back"boned", a.

Defn: Vertebrate.

BACKCAST
Back"cast`, n. Etym: [Back, adv.+ cast.]

Defn: Anything which brings misfortune upon one, or causes failure in an effort or enterprise; a reverse. [Scot.]

BACK DOOR
Back" door".