prismoidaladj.
/prɪzˈmɔɪdl/, U.S. /prɪzˈmɔɪd(ə)l/ 1. Of the form of or relating to a prism or prismoid; approximately prismatic in shape.
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the world > space > shape > angularity > specific angular shape > [adjective] > prismatic
prismatical1611
prismatic1668
diamond-cut1703
prismated1816
prismatoidal1821
prismoidal1826
prismoid1840
prismate1858
the world > relative properties > number > geometry > shape or figure > [adjective] > three-dimensional > prismatical or prismoidal
prismatical1654
prismatoidal1821
prismoidal1826
prismoid1840
prismate1858
1826 W. Kirby & W. Spence Introd. Entomol. IV. xlvi. 266 Prismoidal.., having more than four sides and whose horizontal section is a polygon.
1874 C. P. Smyth Our Inherit. in Great Pyramid ii. 16 After chipping off the prismoidal angles and edges.
1897 Steubenville (Ohio) Herald 29 Apr. 1/2 The form of the solid cut out by the auger is that of two square groins placed base to base. This is a prismoidal solid.
1924 Geogr. Jrnl. 64 391 Prismoidal crystals of very dark or dark green hornblende are thickly distributed throughout the mass.
1956 Amer. Antiq. 21 245/1 Frank Achen of Madison, has a bannerstone of prismoidal form which he found 75 feet south of the area where excavations were conducted.
1990 Marine Geol. 94 239 Black, shiny upper layers of the crust display a prismoidal microstructure and a unique crystallite habit.
2003 Progress in Surface Sci. 72 138 The metal clusters have been found to display a regular prismoidal shape with a flat surface.
2. Designating a kind of monorail consisting of a rail with a large triangular cross-section, apex uppermost, on which the train is mounted as on a saddle. Now historical.
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society > travel > rail travel > railway system or organization > [adjective] > types of track or rail
slow1799
fast1814
fish-jointed1855
prismoidal1874
broad-gauged1881
monorail1885
unballasted1887
sleepered1894
monoline1902
wide gauge1982
1874 Steubenville (Ohio) Daily Herald 22 Dec. 4/2 A contract has been taken to build a railroad on Crew's prismoidal one track system, from the depot in Austin, Texas, to some quarries near that city.
1893 Times 17 Dec. 3/3 It is also claimed that a prismoidal railway, built with a base of 14 inches, angles 45 degrees, can be built at a cost of $3,000 per mile.
1940 Oakland (Calif.) Tribune 15 Dec. 17/4 The Sonoma Valley Prismoidal Railway Company was incorporated in 1875.
1976 Pop. Mech. July 80 The ‘Prismoidal Monorail’..carried Exposition visitors across a ravine to Lauber's Restaurant. Cars and engine..each with one wheel fore and one aft, rode atop a single rail.
Compounds
prismoidal formula n. Mathematics a formula for calculating the volume of a prismoid or truncated pyramid, and hence that of a body or excavation regarded as composed of a number of prismoids.
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1847 Times 22 Jan. 7/6 The prismoidal formula..for ascertaining the cubical contents of bodies of a prismoidal figure.
1853 J. C. Trautwine New Method of Calculating Cubic Contents of Excavations & Embankments 1 There is but one correct principle upon which to calculate the cubic contents of excavations and embankments; and that is, by means of what is known as the Prismoidal Formula.
1911 Encycl. Brit. XVIII. 138/1 The volume of the prismoid is 1/ 6h (A + 4C + B). This is known as the prismoidal formula.
1991 College Mathemat. Jrnl. 22 320 The reader can also derive formula (1) by making the appropriate substitutions in the ‘prismoidal formula’.
This entry has been updated (OED Third Edition, June 2007; most recently modified version published online March 2022).
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adj.1826