a. L. bi- (earlier dui-, cogn. with Gr. δι-, Skr. dvi-) ‘twice, doubly, having two, two-,’ which is in Latin a prefix of adjs., occas. of sbs., rarely of vbs. (e.g., bipertīre). The earliest Latin adjs. of this type are formed by simply prefixing bi- either to adj.- (and verb-) stems, as bifer, bifidus, bijugus, bisonus, or to sb.- (and adj.-) stems, as bicolor, biceps, bifrons, bifurcus, bigener; later in all probability, and more evidently mere compounds, are those in which bi- is prefixed to an adj. with a thematic suffix, as bicorniger, bicubitālis, bilongus, bipatens, and these are occas. participial in form, as bicamerātus, biformātus. The Latin sbs., ending usually in -ium, are formed on the prec. adjs., or possible ones of corresponding type, as biennium a space of two years, biennis lasting two years, biclīnium, *biclīnus.
The prefix entered Eng. in composition, e.g., in bigam (= med.L. bigamus), found c. 1300, bicorne, c. 1420; bifront, biforked occur late in 16th c.; and from the 17th c. onward, by a wide extension of the Latin analogy, especially in its later phases, bi- has been prefixed to any adj. conveniently indicating the thing or quality which is to be described as doubled or occurring twice, principally to those of Latin etymology, as in biangular, bicavitary, bicentral, bivaulted, bivoluminous, but also to others as birainy, biweekly. In modern scientific terminology, adjs. in -ate, -ated are most frequently employed, as biauriculate, bicarinate, bilamellate, bipinnate, biunguiculate, bimaculated; and the attrib. use of sbs. as adjs. tends to such modern forms as bichord, biwhirl. (See also the form BIN-.)
Bi- is therefore used in Eng. to form:—
I. Adjectives, with the sense:—
1. Having or furnished with two —, two- —, as bi-angular, -ate, -ated, -ous, having two angles; bibracteate, having two bracts; bibracteolate, having two small bracts; bicallose, -ous, having two callosities; † bicapited, bicapitate, having two heads, two-headed; bicapsular; bicavitary, having two cavities; bicentral; bichord, having two strings; biciliate, having two cilia or hairs; bicircular, bicolo(u)red, bicolumnar, biconsonantal; bicorporal, -ate, -ated, -eal, having two bodies; bicristate, having two crests; bifacial, bifanged; biglandular, having two glands; bimarginate, bimembral, bimuscular; binodal, having two nodes; binuclear, having two nuclei; bi-ovulate, bipetalous; biporose, having or opening by two pores; bipupillate, having two pupil-like markings; biradiate, having two rays; birainy, having two rains or rainy seasons; bispinous, bistipuled; bitentaculate, having two tentacles; bituberculate, -ated, having two tubercles; bivascular, having two vessels; bivaulted; bivoluminous, consisting of two volumes; biwhirl.
1870. Hooker, Stud. Flora, 259. Peduncles *bi-bracteate at the forks. Ibid., 345. Scale peltate, *bi-bracteolate.
1572. Bossewell, Armorie, II. 42. [Lions] are borne in armes … *Bicapited, Bicorporated, Tricorporated.
1679. Plot, Staffordsh. (1686), 196. The *bicapsular seed vessel of Digitalis ferruginea.
1870. Rolleston, Anim. Life, Introd. 101. Nerve-centres … spoken of as *‘bicavitary.’
1854. Maxwell, in Life, viii. 231. Full of ellipses—bicentral sources of lasting joy.
1857. Berkeley, Cryptog. Bot., § 136. *Biciliate spores.
1880. Athenæum, 20 Nov., 678/3. *Bicircular Quartics.
1862. R. Patterson, Ess. Hist. & Art, 34. A *bi-coloured uniform.
1884. M. Rule, Eadmeri Historia Novorum, Pref. p. lxxxviii. The pages are *bicolumnar.
1861. Max Müller, Sc. Lang., vii. 251. A *biconsonantal root.
1839. Bailey, Festus, viii. (1848), 94. Luxurious, violent, *bicorporate.
1686. Goad, Celest. Bodies, II. iv. 201. Airy Signs, or Signs *Bicorporeal.
1882. R. Brown, Law Kosmic Ord., 57. He meets with a gigantic *bicorporeal Scorpion-couple whose heads reach heaven, whilst their feet are below the Underworld.
1852. Dana, Crust., I. 212. Fourth [joint] prominently *bicristate, the crests thin.
1884. Bower & Scott, De Bary’s Phanerog. F., 48. Firm, leathery … *bifacial leaves.
1851. Richardson, Geol., viii. 315. Small *bifanged molar teeth.
1876. Harley, Mat. Med., 441. Terminal panicles … supported by *biglandular bracts.
1812. J. Jebb, Corr. (1834), II. 77. In these stanzas, each line is obviously *bimembral.
1835. Kirby, Hab. & Inst. Anim., I. viii. 237. The first [order] is *Bimuscular, having two attaching muscles.
1835. Lindley, Introd. Bot. (1848), I. 324. The cyme … may be *binodal, trinodal.
1880. Times, 24 Nov., 10/4. Mr. Ralph Copeland … discovered a small *bi-nuclear, gaseous, planetary nebula.
1881. Gard. Chron., No. 411. 621. Spores … cylindrical, *binuclcate.
1858. W. Clark, Van der Hoeven’s Zool., II. 145. Ventral fins *biradiate.
1855. Maury, Phys. Geog. Sea, v. § 296. Bogota is within the *birainy latitudes.
1852. Dana, Crust., I. 621. The preceding segment is *bispinous.
1877. Huxley, Anat. Inv. Anim., iii. 131. A ciliated *bitentaculate body.
1849. Proc. Berw. Nat. Club, II. vii. 371. A minutely *bituberculated wart.
1809. J. Barlow, Columb., IX. 15. In this *bivaulted sphere.
1870. Lowell, in Athenæum, 19 March, 380. That *bivoluminous shape in which dullness overtakes … genius at last.
1882. in Nature, XXVI. 546. The formation of whirl and *biwhirl systems.
2. Doubly —; — in two ways or directions, on both sides; as bibisalternate (see quot.); bicleft; biconic, -al, conical in two directions; biconcave, biconstant, biconvex; bicrescentic, crescent-shaped on both sides; bicurvate, bifusiform, bipyramidal, birectangular, birefracting, -ive, birefringent, birhomboidal, bi-sphero-concave; bisubstituted.
1817. R. Jameson, Char. Min., 210. When there are two rows of bisalternate planes on each side, as in the *bibisalternate cinnabar.
1627. Drayton, Agincourt, etc., 216. Those sacred springs, which from the *by-clift hill Dropt their pure Nectar.
1854. Woodward, Mollusca (1856), 285. Shell inversely conical, *bi-conic, or cylindrical.
1870. Rolleston, Anim. Life, Introd. 71. The *biconical cavity thus formed.
1833. Lyell, Elem. Geol., xvii. (1874), 291. This Bird approaches the reptilian type in possessing *biconcave vertebræ.
1836. Todd, Cycl. Anat. & Phys., I. 409/1. A biconcave disc.
1880. Nature, XXI. 289. A *bi-constant dispersion formula.
1849–52. Todd, Cycl. Anat. & Phys., IV. 1438/2. When the rays, pass out from a *bi-convex lens.
1854. J. Hogg, Microsc., II. ii. (1867), 400. Spicula having both extremities bent alike—*bicurvate.
1831. Brewster, Optics, xxix. 243. The *bipyramidal dodecahedron.
1869. Tyndall, Notes Light, 75. A *birefracting prism of Iceland spar. Ibid., 66. This crystal is *birefractive.
1880. Nature, XXI. 204. A *birefringent crystal.
1817. R. Jameson, Char. Min., 202. A Crystal is said to be … *Bi-rhomboidal, when its surface consists of … two different rhomboids.
1849–52. Todd, Cycl. Anat. & Phys., IV. 1469/1. *Bi-sphero-concave lenses.
1880. Cleminshaw, trans. Wurtz’ Atom. The., 303. In a *bisubstituted derivate of marsh gas, the third substitution may take place on either side.
3. Bot. and Zool. Twice over, re- —; i.e., having characteristically divided parts which are themselves similarly divided; as BILACINIATE, BIPINNATE, BISERRATE, BITERNATE, q.v.
4. Lasting or continuing for two —; occurring or appearing every two —; as BIENNIAL, bi-hourly, bi-monthly, biweekly.
1843. in Proc. Amer. Philos. Soc., II. 247. *Bi-hourly observations … had ceased with the first of the present year.
1879. Gladstone, in Daily News, 1 Dec., 6/5. Annual as opposed to *bi-monthly or tri-monthly budgets.
b. Occurring or appearing twice in a —; as in bi-diurnal, bi-monthly, bi-quarterly, bi-weekly, bi-winter, bi-yearly. (The ambiguous usage is confusing, and might be avoided by the use of semi-; e.g., semi-monthly, semi-weekly; cf. half-yearly.)
1854. Woodward, Mollusca (1856), 32. A *bi-diurnal visit from the tide.
1878. Print. Trades Jrnl., XXV. 4. A new Spanish *bi-monthly journal.
1884. Pall Mall Gaz., 15 Feb., 16. To issue these etchings in *bi-quarterly numbers.
1885. Farrar, Camb. Bible Sch., Luke xviii. 12, 283. The *bi-weekly fast of the Pharisees…. The days chosen were Thursday and Monday.
1884. C. H. Farnham, in Harper’s Mag., Feb., 394/1. The mail-carriers are making one of their *bi-winter trips on snow-shoes.
1879. Print. Trades Jrnl., XXVIII. 9. A *bi-yearly calendar.
c. The prec. adjs. in -ly are also used adverbially.
1864. Even. Standard, 29 Oct. Sixpenny parts, to be issued bi-monthly.
1865. Reader, 12 Aug., 188/3. To be held bi-weekly, on Mondays and Thursdays.
5. Joining or connecting two —; as BI-ACROMIAL, BI-ISCHIATIC, BI-PARIETAL, q.v.
6. Occasionally in other senses, as bimanual, employing two hands; BISERIATE, arranged in two series; bitaurine, belonging to two bulls.
1872. T. G. Thomas, Dis. Women, 73. The practice of *bimanual palpation.
1882. Vines, Sachs’ Bot., 430. The *biseriate segmentation of the apical cell.
1864. E. Swifte, in N. & Q., V. 142. The *bitaurine bellow.
II. Adverbs, verbs, and substantives; chiefly a. derivatives from the adjectives in I, as biconically adv. (f. biconical in 2), bicleavage (cf. bicleft in 2), bicoloration (cf. L. bicolor and bicoloured in 1), BIVOCALIZE v.; but also b. substantives formed after Latin analogies, in which bi- has the force of ‘double, two’; as bimillionaire, the owner of property valued at two millions of money; binomenclature, double naming; biprong, a two-pronged fork.
a. 1881. Jrnl. Linn. Soc., XV. No. 87. 390. Shell … *biconically fusiform.
1847–9. Todd, Cycl. Anat. & Phys., IV. 676/2. A *bicleavage of the azygos ventral rays.
1877. Coues, Fur Anim., iv. 120. [The] animal … resumes its *bicoloration.
b. 1838. New Month. Mag., LIV. 314. The millionaire … becomes a *bi-millionaire.
1873. Tristram, Moab, vii. 120. Another instance of *binomenclature, a duplicate name occurring on the east side.
1872. M. Collins, Pr. Clarice, I. xii. 114. The ancient *biprong of steel.
III. Chem. Substantives and adjectives, in which bi- signifies the presence in a compound of twice that amount (usually two equivalents) of the acid, base, etc., indicated as present by the word to which it is prefixed. Thus carbonate of soda was viewed as containing one equivalent of carbonic acid, bicarbonate of soda as containing two. In recent chemical nomenclature, bi- has been systematically superseded by di-.
1863. Watts, Dict. Chem., I. 584. *Bi-compounds: see Di-compounds.
1819. Brande, Chem., v. § 306. *Bicarbonate of Potassa is formed by passing a current of carbonic acid into a solution of the subcarbonate.
1869. Roscoe, Elem. Chem., 210. The *bicarbonate [of soda] is chiefly used … for the production of refreshing drinks.
1826. Henry, Elem. Chem., II. 45. The second sulphuret, or *bi-sulphuret of tin.
1850. Daubeny, Atom. The., x. (ed. 2), 342. *Bisulphuretted hydrogen is … decomposed by the action of alkalies.
1863. Tyndall, Heat, i. 14. I wet a pellet of cotton wool with liquid *bisulphide of carbon.
1879. G. Gladstone, in Cassell’s Techn. Educ., IV. 213/1. Tartar emetic—the *bitartrate of antimony and potash.
