sesqui-

sesqui-
  (ˈsɛskwɪ)
  a Latin prefix [L. sesqui-, also sesque-, contraction of *sēmis-que a half in addition; cf. sestertius:—*sēmis-tertius], expressing a superparticular ratio.
  1. a. With designations of measure or amount, denoting one-and-a-half times the unit; as sesquihōra an hour and a half; sesquipēs a foot and a half (see sesquipedalian); so † sesquiˈhoral a., lasting an hour and a half; ˌsesquioˈcellus Ent. (see sesquialterous); † ˈsesquitone Mus., an interval consisting of a tone and a semitone, a minor third; also used loosely in † sesquiˈdecuman a., consisting of fifteen; † sesquiˈdecury, a set of fifteen.

1650 Descr. Future Hist. Eur. 31 Merlin prophesied to him, ‘That within lesse then a *sesquidecumane period of time, the Eagles head should be cloven in two.’

1650 Ravis (title) A generall Grammer for the ready attaining of the Ebrew... Also a *Sesquidecury, or a number of Fifteene Adoptive Epistles..concerning care of the Orientall Tongues to be promoted.

1652 Urquhart Jewel Wks. (1834) 279 Their tedious pharisaical prayers before supper, and *sesquihoral graces upon a dish of skink and leg of mutton.

1694 W. Holder Harmony 80 The Third Minor, Trihemitone, or *Sesquitone, as consisting of three half Tones (or rather of a Tone and half a Tone).

  b. Chem. In the names of salts, expressing a proportion of 3 to 2 between the constituents, viz. a combination of 3 atoms or equivalents of the substance denoted by the word to which it is prefixed with 2 atoms of another element or radical; e.g. sesquibromide, a bromide containing 3 atoms of bromine for 2 of another substance; similarly sesquiˈbasic [see basic a.], having 3 equivalents of the base for 2 of the acid; ˈsesquiˌcompound, ˈsesquiˌsalt, a compound, a salt having its constituents in these proportions; sesquiˈterpene, -ˈterpenoid, any terpene having the formula C₁₅H₂₄; any simple derivative of such a compound.
  This terminology was introduced into English by T. Thomson in his First Principles of Chemistry 1825, and System of Chemistry 1831, where many terms, not illustrated here, are to be found.

1849 D. Campbell Inorg. Chem. 208 The *Sesquibasic acetate of lead, 3PbO,2(C4H3O) + Aq.

1831 T. Thomson Syst. Chem. (ed. 7) II. 388 *Sesquiborate of ammonia.

Ibid. I. 324 The *sesquibromide of arsenic.

1825 ― 1st Princ. Chem. II. App. 515 *Sesquicarbonate of ammonia. 1883 T. F. Hardwich Photogr. Chem. (ed. 9) 38 When first formed it has nearly the composition of a Sesquicarbonate, but by exposure to the air neutral Carbonate of Ammonia escapes, and a white powder is left, which is a Bicarbonate.

1871 Jrnl. Chem. Soc. XXIV. 1012 *Sesquicarbonyl Chloroplatinite, C3O3Pt2Cl4.

1825 T. Thomson 1st Princ. Chem. II. App. 515 *Sesquichloride of iron.

1857 Miller Elem. Chem., Org. (1862) 218 Aluminum forms a *sesqui-compound (Al2(C4H5)3) corresponding to its oxide Al2O3.

1839 Penny Cycl. XIII. 32/2 The ferrocyanide of potassium also gives a deep blue, but the *sesquiferrocyanide gives none at all.

1831 T. Thomson Syst. Chem. (ed. 7) II. 452 *Sesquihydrated carbonate of soda.

1887 Jrnl. Chem. Soc. LII. i. 558 The formula of the fibrous alum, 3MgO,SO3 + 2Al2O3,3SO3 + 53H2O, represents a *sesqui-magnesia alum.

1849 D. Campbell Inorg. Chem. 186 *Sesquinitrate of iron, Fe2O33NO5.

1839 Penny Cycl. XIII. 32/1 Sulphate of Peroxide of Iron, or *Sesquipersulphate of Iron.

Ibid., [Pernitrate of iron] is..a *sesquisalt.

1825 T. Thomson 1st Princ. Chem. II. App. 515 *Sesquisulphate of uranium.

Ibid., *Sesquisulphuret of arsenic. 1890 Westm. Gaz. 1 Mar. 6/1 It has been found that sesqui-sulphuret of phosphorus..melts only at 142 deg.

1838 T. Thomson Chem. Org. Bodies 176 *Sesquitartrovinate of copper.

1888 Jrnl. Chem. Soc. LIV. 377 *Sesquiterpene, C15H24. 1922 Nature 16 Feb. 226/2 The principal constituents identified are safral, camphor, pinene, sesquiterpenes, eugenol, and alcoholic bodies. 1966 New Scientist 8 Dec. 576/2 The substance..is derived from farnesol, one of the basic sesquiterpenes, vegetable substances..which imitate the function of the juvenile hormone. 1976 Nature 5 Aug. 487/2 The essential oils d-bornyl acetate, α- and β-santalol and several plant sesquiterpene hydrocarbons have been shown to induce sexual excitement in male American cockroaches.

1951 Jrnl. Chem. Soc. 2988 (heading) *Sesquiterpenoids... Evidence for a nine-membered ring in caryophyllene. 1976 Nature 5 Aug. 488/2 Cadinol, a sesquiterpenoid biogenetically related to germacrene D, has been isolated from a plant and shown to be a stimulant for both male and female cockroaches.

  c. In Astrol., sesquiquadrate, -quartile, denoting an aspect of planets when 135° from one another; sesquiquintile, when 108° from one another; sesqui-square = sesquiquadrate.

c 1610 Sir C. Heydon Astrol. Disc. (1650) 95 The *Sesquiquadrate [aspect] of 135 degr. 1647 Lilly Chr. Astrol. c. 512.

1674 S. Jeake Arith. (1696) 11 Aspects..*Sesquiquartil.

1647 Lilly Chr. Astrol. c. 512 *Sesquiquintil [consists of degrees] 108.

1861 ‘Zadkiel’ Hand-bk. Astrol. I. 8 The new aspects are semi-square, 45°; quintile, 72°; *sesqui-square, 135°.

  † d. Prefixed to words descriptive of forms of religious belief, = extreme(ly), excessive(ly), ultra-; e.g. sesqui-conformist, sesqui-deist, sesqui-heretic, sesqui-Jesuit, sesqui-separation; also sesqui-superlative adj. Obs.

a 1661 Fuller Worthies, Glouc. (1662) i. 360 Some pressed super-Canonical Ceremonies, and such *Sesqui-Conformists made Mr. Workman turn first but a Semi-Conformist, and then by degrees to renounce all Conformity.

1880 F. Hall Doctor Indoctus 52 If he invented a brand-new form of allotheism, and came out a *sesquideist, or a quaternitarian.

1627 Donne Serm. i. (1649) II. 5 They are *se[s]qui-Heretiks in this, that they countenance Incontinency, and Fornication, which those very heretiks abhorred.

a 1631 ― Serm. xii. (1640) 113 A Jesuit, or a Semi-Jesuit, a practising Papist, or a *Sesqui-Jesuit, a Jesuited Lady.

1653 R. Baillie Dissuas. Vind. (1655) 9 Why..do the Independents..runne beyond it..to a *sesqui-separation?

1611 Donne Poems, Upon Coryat's Crudities 2 Oh, to what height will love of greatness drive Thy learned spirit, *sesqui-superlative!

  2. a. With an ordinal numeral adjective, denoting the proportion 1 + 1 / n :1, i.e. n + 1:n, where n is the corresponding cardinal number, as sesquioctāvus, bearing the ratio 1¹/₈:1, i.e. 9:8; so sesquialter, -altera, etc., sesquitertia, etc.; † ˌsesquibiˈtertial, involving a proportion of 5:3; † ˌsesquiˈdecimal, of 11:10; sesquiˈnonal, of 10:9; ˌsesquiocˈtaval, -ˈoctave, of 9:8; ˌsesquiˈquartal, -quartan, of 5:4; ˌsesquiˈseptimal, of 8:7.

a 1696 Scarburgh Euclid (1705) 228 Sextuple proportion is by addition of the Antecedents made of Sesquitertial, *Sesquibitertial, and Triple proportions.

Ibid. 180 If above the exact Multiple of the Consequent, there remains in the Antecedent any Quotal part of the Consequent, as an half, a third, a fourth, or a tenth part of the Consequent, (or otherwise thus named, a Sesquialteral, a Sesquitertial, a Sesquiquartal, a *Sesquidecimal part, &c.).

1787 Hawkins Life of Johnson 375 The proportion of a column is taken from that of the human figure, which..is in a man sesquioctave of the head, and in a woman *sesquinonal.

a 1696 Scarburgh Euclid (1705) 182 The Exponent of their proportions is the common Quotient 11/8, which shews the proportion to be..*Sesquioctaval.

1603 Holland Plutarch's Mor. Explan. Words, *Sesqui-octave, that which compriseth the whole and one 8 part; as 9 to 8. 18 to 16. 1726 Leoni Alberti's Archit. II. 30/2 Its proportion will be as eight to nine, which the Latins call a Sesquioctave.

a 1696 Scarburgh Euclid (1705) 180 This proportion is named triple *Sesquiquartal, and is noted thus 31/4.

1715 tr. Gregory's Astron. (1726) I. p. xi, The same Tension upon a sub⁓sesquialteran Chord acts in a double *sesquiquartan Ratio.

1726 Leoni Alberti's Archit. II. 30/2 Seven to eight,..the proportion which the Latins call *Sesquiseptimal.

  b. in Music, after sesquialtera and sesquitertia; sesquiquarta, -quinta, -sexta, -octava (-octave), -nona, applied (i) to harmonic intervals producible by sounding four-fifths, five-sixths, etc. of a given string; (ii) rhythmic combinations of four notes against five, five against six, etc.

1597 Morley Introd. Mus. 54 If they would make fiue crotchets to one semibreefe, then must they set downe Sesquiquarta proportion thus 4/5, wherein fiue semibriefes or their value make vp the time of foure semibriefes or strokes. 1694 W. Holder Harmony 153 To divide a Sesquioctave Tone (9 to 8) by dupling the Terms of the Ration thereof, into 2 Hemitones. 1698 Wallis in Phil. Trans. XX. 81 We assign to a Fifth..the Sesqui-alter Proportion..And to a Tone..The Sesqui-octave (or that of 9 to 8). 1776 Hawkins Hist. Mus. I. 74 The ditone he had demonstrated to be in sesquiquarta proportion, as 5 to 4. Ibid. 75 The greater or sesquioctave tone, 9 to 8, and the lesser or sesquinonal tone, 10 to 9. Ibid. The semiditone is sesquiquinta. 1883 Rockstro in Grove's Dict. Mus. III. 475/1.

Oxford English Dictionary