The series of vertebrae, separated by disks, that encloses and protects the spinal cord, and runs down the middle of the back in vertebrate animals.

A sudden backward motion. / (figuratively) A negative reaction, objection or outcry, especially of a violent or abrupt nature.

To cause or set off a backlash.

(basketball) The flat vertical surface to which the basket is attached.

(medicine, transitive) To place (a patient) on a spine board.

(nautical) The port or larboard side of a ship

ionizing radiation that is naturally present in the environment.

One who, or that which, backs; especially one who backs an entrant in a contest, or who supports an enterprise by funding it.

(phonetics) comparative form of back: more back

With the back of the hand. / Involving a backward flip of the hand. / Insincere, sarcastic, ironic, or self-contradictory. / Indirect. / Backwards, turned around. / (of writing) inclining to the left