A long slender rod with a rake-like device on one end, sometimes in the form of a human hand, designed to let a person scratch their own back.

A backhanded stroke or blow. / (swimming) A stroke swum lying on one's back, while rotating both arms through the water as to propel the swimmer backwards.

To swim the backstroke.

A thing or a person put in the rear or in the back of something to reinforce, hold, support. / A default arrangement that holds if all else fails. / (baseball) A wall or fence behind home plate.

(transitive) To serve as backstop for. / (transitive) To bolster, support.

The key on a typewriter that moves the head one position backwards. / (computing) A keyboard key used for removing a character behind the cursor, and moving the cursor one position backwards.

(computing) To remove a character behind a cursor. / (computing) To move a magnetic tape to a previous block.

(transitive) to attack someone (especially verbally) unfairly in a deceitful, underhand, or treacherous manner, especially when they're not present in the place or situation that it happens. (as if stabbing them in the back). See backbite.

The back side of an estate: the backyard and outbuildings behind a main house, especially (UK dialect, euphemistic) an outhouse. / (euphemistic) A person's buttocks.

(board sports) Approaching an obstacle backward / Used other than figuratively or idiomatically: see back, side.