back up (v.) Look up back up at Dictionary.com
1767, "stand behind and support," from back (v.) + up. The noun meaning "a standby, a reserve" is recorded from 1952 (often written as one word, backup); specific reference to computing is from 1965.
back-ache (n.) Look up back-ache at Dictionary.com
c.1600, from back (n.) + ache (n.).
back-formation (n.) Look up back-formation at Dictionary.com
also back formation, by 1887, from back (adv.) + formation.
back-stitch (n.) Look up back-stitch at Dictionary.com
1610s, from back (adj.) + stitch (n.).
back-to-nature (adj.) Look up back-to-nature at Dictionary.com
first attested 1915.
backbencher (n.) Look up backbencher at Dictionary.com
1874 in the House of Commons sense, from back (adj.) + bench (n.); occupants of the rear seats being the least-prominent politicians.
backbiting (n.) Look up backbiting at Dictionary.com
c.1200, bacbitunge, from back (adj. or n.) + biting. Related: back-bite (v.), early 14c.; back-biter (c.1200).
backbone (n.) Look up backbone at Dictionary.com
"spine," early 14c., from back (n.) + bone (n.). Figurative sense of "strength of character" is attested from 1843.
backdate (v.) Look up backdate at Dictionary.com
also back-date, by 1881 (implied in back-dated), from back (adv.) + date (v.1). Compare antedate. Related: Backdated; backdating.
backdoor (adj.) Look up backdoor at Dictionary.com
also back-door, "devious, shady, illegal," 1640s. The notion is of business done out of public view. The noun back door in the literal sense is from 1520s, from back (adj.) + door. The association with sodomy is at least from 19c.; compare also back-door man "a married woman's lover," black slang, early 20c.
backdrop (n.) Look up backdrop at Dictionary.com
1913, in U.S. theatrical argot, from back (adj.) + drop (n.).
backer (n.) Look up backer at Dictionary.com
"supporter," 1580s, agent noun from back (v.).
backfill (n.) Look up backfill at Dictionary.com
1901 (as backfilling), from back (adj.) + fill (n.). The verb was in use by 1930.
backfire (n.) Look up backfire at Dictionary.com
1839, American English, originally "a fire deliberately lit ahead of an advancing prairie fire to deprive it of fuel," from back (adj.) + fire (n.). As a verb in this sense, recorded from 1886. The meaning "premature ignition in an internal-combustion engine" is first recorded 1897. Of schemes, plans, etc., "to affect the initiator rather than the intended object" it is attested from 1912, a figurative use from the accidental back-firing of firearms.
backgammon (n.) Look up backgammon at Dictionary.com
1640s, baggammon, the second element from Middle English gamen, ancestor of game; the first element apparently because pieces sometimes are forced to go "back." Known 13c.-17c. as tables.
background (n.) Look up background at Dictionary.com
1670s, from back (adj.) + ground (n.); original sense was theatrical, later applied to painting. Figurative sense is first attested 1854.
backhand (n.) Look up backhand at Dictionary.com
as a tennis stroke, 1650s, from back (adv.) + hand. As a verb, by 1935. The figurative adjectival sense of "indirect" is from c.1800. Related: Backhanded; backhanding.
backhoe (n.) Look up backhoe at Dictionary.com
by 1928, from back (n. or adj.) + hoe (n.).
backing (n.) Look up backing at Dictionary.com
1590s, "support;" 1640s, "retreat;" verbal noun from back (v.). Physical sense of "anything forming a backing to something else" is from 1793. Meaning "musical accompaniment" is recorded from 1940.
backlash (n.) Look up backlash at Dictionary.com
1815, of machinery, from back (adj.) + lash (n.). In metaphoric sense, it is attested from 1955.
backless (adj.) Look up backless at Dictionary.com
1926, in reference to women's clothing, from back (n.) + -less.
backlist (n.) Look up backlist at Dictionary.com
1946, in publishing, from back (adj.) + list (n.). As a verb, "to put on the back list," from 1983. Related: Backlisted.
backlog (n.) Look up backlog at Dictionary.com
1680s, "large log placed at the back of a fire," from back (adj.) + log (n.1). Figurative sense of "something stored up for later use" is first attested 1883, but this and the meaning "arrears of unfulfilled orders" (1932) might be from, or suggested by, log (n.2).
backorder Look up backorder at Dictionary.com
also back-order, by 1980 (n.); 1985 (v.), from back (adj.) + order. Related: Backordered.
backpack Look up backpack at Dictionary.com
1914 as a noun, 1916 as a verb, from back (n.) + pack (n.). Related: Backpacked; backpacking.
backside (n.) Look up backside at Dictionary.com
c.1400, from back (adj.) + side (n.). In the specific sense of "rump, buttocks" it is first recorded c.1500.
backslash (n.) Look up backslash at Dictionary.com
1982, new punctuation symbol introduced for computer purposes, from back (adj.) + slash (n.).
backslide (v.) Look up backslide at Dictionary.com
in the religious sense, 1580s, from back (adj.) + slide (v.). Related: Backslider; backsliding (1550s).
backspace (adj.) Look up backspace at Dictionary.com
also back-space, 1899, in reference to keyboarding, from back (adv.) + space.
We have had the pleasure of examining one of the 1899 model Hammond typewriters, with the new back-space key. This new feature is certainly an improvement in the machine. ["The Phonetic Journal," March 11, 1899]
backstabber (n.) Look up backstabber at Dictionary.com
also back-stabber, in the figurative sense, 1839, from back (n.) + agent noun from stab (v.). The verb backstab in the figurative sense is from 1925.
backstage Look up backstage at Dictionary.com
also back-stage, 1898, from back (adj.) + stage (n.).
backstairs Look up backstairs at Dictionary.com
"stairs at the back of a structure," 1650s, from back (adj.) + stairs (see stair). Figurative use is attested earlier (1640s).
backstop (n.) Look up backstop at Dictionary.com
1819, in cricket, from back (adj.) + stop (n.). In U.S. baseball, from 1889, "fence behind the catcher;" figurative extension to "catcher on a baseball team" is from 1890. The verb is attested from 1956 in the sense of "support." Related: Backstopped; backstopping.
backstory (n.) Look up backstory at Dictionary.com
c.1990, from background story.
backstreet (n.) Look up backstreet at Dictionary.com
mid-15c., from back (adj.) + street.
backstroke (n.) Look up backstroke at Dictionary.com
1670s, "counter-punch," from back (adj.) + stroke (n.). From 1876 in swimming, from back (n.).
backtalk (n.) Look up backtalk at Dictionary.com
also back-talk, "impertinent retort," 1858, originally often used in literary attempts at low Irish idiom, from back (adj.) + talk (n.).
backtrack (v.) Look up backtrack at Dictionary.com
"retrace one's steps," figuratively, by 1896, from literal sense, with reference to hunted foxes, from back (adv.) + track (v.). Related: Backtracked; backtracking.
backup Look up backup at Dictionary.com
see back up.
backward (adv.) Look up backward at Dictionary.com
c.1300, from abakward, from Old English on bæc (see back (adv.)) + -weard adjectival and adverbial suffix (see -ward). Old English had the adverb bæcling. As an adjective, from 1550s. Meaning "behindhand with regard to progress" is first attested 1690s. To ring bells backward (from lowest to highest), c.1500, was a signal of alarm for fire or invasion, or to express dismay. Another Middle English word for "backward, wrongly" was arseward (c.1400).
backwardness (n.) Look up backwardness at Dictionary.com
1580s, from backward + -ness.
backwards (adv.) Look up backwards at Dictionary.com
1510s, from backward with adverbial genitive. Figurative phrase bend over backwards is recorded from 1901.
backwash (n.) Look up backwash at Dictionary.com
1876, "motion of a receeding wave," from back (adj.) + wash (n.).
backwater (n.) Look up backwater at Dictionary.com
late 14c., "water behind a dam," from back (adj.) + water (n.1). Hence flat water without a current near a flowing river, as in a mill race (1820); figurative use of this for any flat, dull place is from 1899.
backwood (n.) Look up backwood at Dictionary.com
1709, American English, from back (adj.) + wood (n.) "forested tract." Also backwoods. As an adjective, from 1784.
BACKWOODSMEN ... This word is commonly used as a term of reproach (and that, only in a familiar style,) to designate those people, who, being at a distance from the sea and entirely agricultural, are considered as either hostile or indifferent to the interests of the commercial states. [John Pickering, "A Vocabulary, or Collection of Words and Phrases Which Have Been Supposed to be Peculiar to the United States of America," Boston, 1816]
backyard (n.) Look up backyard at Dictionary.com
also back-yard, 1650s (perhaps early 15c.), from back (adj.) + yard (n.1).
bacon (n.) Look up bacon at Dictionary.com
early 14c., "meat from the back and sides of a pig" (originally either fresh or cured, but especially cured), from Old French bacon, from Proto-Germanic *bakkon "back meat" (cognates: Old High German bahho, Old Dutch baken "bacon"). Slang phrase bring home the bacon first recorded 1908; bacon formerly being the staple meat of the working class.
bacteria (n.) Look up bacteria at Dictionary.com
1847, plural of Modern Latin bacterium, from Greek bakterion "small staff," diminutive of baktron "stick, rod," from PIE *bak- "staff used for support" (also source of Latin baculum "rod, walking stick"). So called because the first ones observed were rod-shaped. Introduced as a scientific word 1838 by German naturalist Christian Gottfried Ehrenberg (1795-1876).
bacterial (adj.) Look up bacterial at Dictionary.com
1869, from bacteria + -al (1).
bacteriology (n.) Look up bacteriology at Dictionary.com
1884, from German; see bacteria + -ology. Related: Bacteriological (1886). Bacteriological warfare is from 1924.