triangularadj.n.
/trʌɪˈaŋɡjʊlə/ 1.
a. Having, or arranged in, the form of a triangle; contained by three sides and angles; three-cornered, three-sided.
ΘΚΠ
the world > space > shape > angularity > specific angular shape > [adjective] > triangular
three-corneredc1400
three-squaredc1400
three-squarec1450
triangle1474
triangled1486
triangular?1541
three-corner1548
trilater1570
trigonal1571
three-corned1584
three-sided1601
triangulated1610
triangulate1611
triform1621
triangulary1622
triquetrous1658
trilateral1660
triagonal1665
trigonic1788
cocked hat1846
heater-shaped1847
the world > relative properties > number > geometry > shape or figure > [adjective] > two-dimensional > triangular
triangle1474
triangled1486
triangular?1541
trigonal1570
trilater1570
triangulated1610
triangulate1611
triform1621
triangulary1622
triquetrous1658
trilateral1660
trilineal1715
trilinear1715
trigonic1788
trigonate1815
triagonal1831
?1541 R. Copland Guy de Chauliac's Questyonary Cyrurgyens ii. sig. Eiv The bony substaunce [of the nose] hath two trianguler bones wherwith the brydge is reysed vp.
1590 E. Spenser Faerie Queene ii. ix. sig. V6 The frame thereof seemd partly circulare, And part triangulare.
c1660 J. Evelyn Diary anno 1644 (1955) II. 99 A triangular building of brick.
1776 W. Withering Brit. Plants (1796) II. 375 Populus... Leaves nearly triangular, toothed and angular.
1825 W. Scott Talisman i, in Tales Crusaders III. 6 His triangular shield suspended round his neck.
b. Situated at the angular points of a triangle. (In quots. quasi-adv.) ? Obsolete.
ΘΚΠ
the world > space > shape > angularity > specific angular shape > [adjective] > triangular > situated at the points of a triangle
triangular1622
1622 M. Drayton 2nd Pt. Poly-olbion xxii. 50 Three..hils that stand Trianguler.
1707 J. Mortimer Whole Art Husbandry (1721) II. 74 3 or 4 quarter Stakes set triangular or quadrangular.
c. Having three edges, as a prism or pyramid; three-edged, trihedral, triquetrous.
ΘΚΠ
the world > space > shape > angularity > specific angular shape > [adjective] > triangular > pyramidal or triangular in section
pyramidalc1450
trigonal1571
pyramidate1572
pyramidical1599
pyramidy1627
pyramical1633
triangular1644
pyramidated1745
triquetrous1752
trihedral angle1789
pyramoidal1883
1644 K. Digby Two Treat. i. xxix. 257 Those..cunning in Optikes..by refractions..make all sortes of colours out of pure light: as we see..in..triangular glasses, or prismes.
1665 T. Herbert Some Years Trav. (new ed.) 384 Other strange Fish we had..some were globous, others triangular.
1728 E. Chambers Cycl. at Pyramid The Pyramid is said to be Triangular, Quadrangular, Quinquangular, &c. as the Base is triangular, quadrangular, &c.
1807 C. Hutton Course Math. (ed. 5) II. 262 To find the Number of Balls in a Triangular Pile.
1852 H. B. Stowe Uncle Tom's Cabin I. vi. 72 The small, sharp, triangular beech-nuts lay scattered thickly on the ground.
1873 E. Spon Workshop Receipts 1st Ser. 330/2 Triangular glovers' needles for sewing up skins.
d. Contained by triangles, as a solid figure; of which the faces are triangles. rare.
ΚΠ
1816 R. Jameson Treat. External Characters Minerals (ed. 2) 139 Triangular Dodecahedron..consists of two six-sided pyramids, joined base to base.
2.
a. Pertaining or relating to a triangle: as triangular compasses, a kind of compasses with three legs, used for taking off triangles; triangular co-ordinates (Geometry), a kind of trilinear co-ordinates. triangular quadrant: see quot. 1706.
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the world > relative properties > measurement > measuring instrument > [noun] > for measuring distances > compasses, dividers, or callipers
compassa1387
proportional compass1570
callipers1571
calliper compass1581
triangular compasses1701
dividers1703
cannipers1707
hair-compasses1728
bow-compass1796
outside calliper1874
wing-compass1875
moff1885
odd-leg1900
1701 T. Tuttell Descr. Math. Instruments in J. Moxon Math. made Easie (ed. 3) 21 Triangular Compasses, containing 3 Legs or Feet, to take off at once any Triangle used on Maps, Globes, etc.
1706 Phillips's New World of Words (new ed.) Triangular Quadrant, is a Sector with a loose Piece to make it an Equilateral Triangle; having the Calendar graduated on it, with the Sun's Place, Declination, &c. It is an Instrument of great Use in the Arts of Dialling, Navigation, and Surveying.
1807 T. Young Course Lect. Nat. Philos. I. x. 102 Triangular compasses are sometimes used for laying down a triangle equal to a given triangle.
b. triangular numbers n. (also elliptical as triangulars) the first series of polygonal numbers (1, 3, 6, 10, 15, 21, etc.; see polygonal adj. 2), obtained by continued summation of the natural numbers 1, 2, 3, 4, 5, 6, etc.: see quot. 1837.
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the world > relative properties > number > mathematical number or quantity > numerical arrangement > [noun] > set > sequence > series > of polygonal numbers
pentagonal number1670
triangular numbers1706
pentagonal1795
1706 W. Jones Synopsis Palmariorum Matheseos 165 In a Rank of Triangulars their Sums are called Triangulars or Figurates of the 3d Order.
1796 C. Hutton Math. & Philos. Dict. (new ed.) I. 468/2 The triangular numbers 1, 3, 6, 10, 15, &c.
1798 C. Hutton Course Math. I. 214 The sides or faces in either the triangular or square piles, are called arithmetical triangles; and the numbers contained in these, are called triangular numbers.
1837 C. Babbage 9th Bridgewater Treat. ii. 37 (note) They are called triangular numbers, because a number of points corresponding to any term can always be placed in the form of a triangle.
3. figurative. Relating to or taking place between three persons or parties, three-sided; also, constituting a triad or set of three, threefold, triple; spec. with reference to the ‘eternal triangle’ (see triangle n. 1c).
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the world > relative properties > number > specific numbers > three > condition of being threefold > [adjective]
thrilec725
threefoldc1000
treblec1374
trinec1386
thrinfalda1400
tripartitec1420
triparted1429
ternaryc1430
trinary1474
triplicate?a1475
trivial?a1475
triplage1526
threefolded1528
triple1552
treblefold1561
trifold1578
trinal1590
tripart1592
ternal1599
triplexa1616
tergeminous1656
ternarious1656
triplasian1678
triplet1697
ternarian1732
triangular1812
Trinitarian1812
triplasic1864
three-body1936
triplexed1974
the world > relative properties > number > specific numbers > three > condition of being threefold > [adjective] > involving three parties
triangular1812
three-way1961
society > morality > moral evil > licentiousness > unchastity > fornication, adultery, or incest > [adjective] > adulterous > where adultery exists in marriage
triangular1880
1812 T. Jefferson Writings (1830) IV. 175 The triangular war must be an idea of the Anglomen and malcontents.
1816 T. L. Peacock Headlong Hall xv. 215 Avarice, luxury, and disease constitute the triangular harmony of the life of man.
1871 W. White Jrnl. (1898) 244 We had an interesting triangular talk.
1880 T. Hardy Fellow-townsmen v. 44 The triangular situation—himself, his wife, Lucy Savile—was the one clear thing.
1908 Times 9 July 15/5 [The Australians] were unable to take part in the suggested triangular contest in this country next year.
a1914 Mod. In these elections there will be several triangular contests.
1914 W. L. George Dramat. Actualities 39 The difficulties of matrimony, triangular or other, financial or monetary entanglements.
1968 S. Hynes Edwardian Turn of Mind vi. 181 The hero [is] involved in a triangular situation that Shaw took from his own amatory experience.
1976 Southern Evening Echo (Southampton) 13 Nov. 13/7 The Mid-Hants (Southampton) girls' netball teams had a successful time in a triangular tournament against Derbyshire and Berkshire at Reading.
1977 Gay News 24 Mar. 24/4 Husband, wife and female lodger involved in a triangular relationship.
Compounds
C1.
a. Parasynthetic, as triangular-bodied, triangular-headed, triangular-leaved, triangular-pointed, triangular-spotted; also triangular-wise adv.
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the world > space > shape > angularity > specific angular shape > [adverb] > triangle
triangle1474
trianglewise?1523
three-corneredwise1580
triangularly1604
triangle-ways1689
triangular-wise1707
three-corner-ways1748
three-corner-wise1862
1707 J. Mortimer Whole Art Husbandry (1721) I. 189 Placing another Row at the Ends where the forked Sticks meet Triangular-wise.
1731 P. Miller Gardeners Dict. I. at Aloe The upright triangular-leav'd viscous Aloe.
1769 J. Parsons in Philos. Trans. 1768 (Royal Soc.) 58 194 The triangular-headed Cameleons.
1804 G. Shaw Gen. Zool. V. 420 Triangular-bodied, unarmed Trunk-Fish.
1823–5 J. E. Smith Eng. Flora (1828) II. 9 Mercury Goose~foot. Leaves triangular-arrow-shaped, entire.
b. Botany. In combination with other adjectives of form, as triangular-cordate, triangular-crenate, triangular-dentate, triangular-hastate, triangular-ovate, triangular-rhomboid, triangular-subulate.
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1870 J. D. Hooker Student's Flora Brit. Islands 264 Scrophularia nodosa..leaves ovate or triangular-cordate.
1887 W. Phillips Man. Brit. Discomycetes 99 Margin triangular-dentate.
C2.
triangular trade n. a multilateral system of trading in which a country pays for its imports from one country by its exports to another; spec. (Historical) in the slave trade (see quots.).
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society > trade and finance > other trading methods > [noun]
fair trading1685
grocery1689
carriage trade1720
sale or (formerly and) return1795
Labour Exchange1828
security system1831
smousingc1876
postal trade1902
triangular trade1934
switch trading1967
relationship management1970
p-y-o1977
counter-trade1978
pick-your-own1980
counter-trading1983
fair trade1986
carry trade1994
1934 C. M. MacInnes England & Slavery iii. 39 After the Restoration a great triangular trade developed between England, the West Coast of Africa and the West Indies or the continental colonies.
1948 T. S. Ashton Industr. Revol. 1760–1830 ii. 47 Cloth, firearms, hardware, and trinkets were sent to Africa and exchanged for slaves, who were shipped to the West Indies to pay for the luxuries and raw material which constituted the final cargo in this disreputable, triangular trade.
1971 C. Plimmer & D. Plimmer Damn'd Master ii. 26 With the profits from the sale of the slaves in the West Indies they bought sugar..which, back in Europe, they sold for a second profit with which in turn they bought more goods... This became known as the triangular trade.
This entry has not yet been fully updated (first published 1914; most recently modified version published online December 2020).
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adj.n.?1541