cubic, a. and n.
(ˈkjuːbɪk)
[a. F. cubique (Oresme, 14th c.), ad. L. cubicus, a. Gr. κυβικός, f. κύβος cube.]
A. adj.
1. a. Of the form of a cube; cubical.
| 1551 Recorde Pathw. Knowl. i. Defin., A dye, whiche is called a cubike bodie by geometricians. 1622 Peacham Compl. Gentl. ix. (1634) 76 If they would double the Altar in Delos, which was of cubique forme. 1710 Lond. Gaz. No. 4691/4 The said Sword [has] the Pummel of a Cubick form. 1874 tr. Lommel's Light 56 A cubic vessel the sides of which are made of glass. |
b. Min. Applied to certain minerals which crystallize in cubes or similar forms; as cubic alum, alum-stone or alunite; cubic nitre, sodium nitrate.
| 1782 Withering in Phil. Trans. LXXII. 336 Cubic nitre. 1791 Hamilton Berthollet's Dyeing I. i. iii. ii. 254 A dissertation on cubic alum. 1877 Watts Dict. Chem. IV. 105 Nitrate of sodium crystallises in obtuse rhombohedrons, which on cursory inspection have very much the aspect of cubes; hence the name cubic saltpetre. |
c. Cryst. Another name for the Isometric system, in which the three axes are equal and mutually at right angles; the cube being a typical form of the system.
| 1878 Gurney Crystallogr. 37 Crystals possessing this highest possible degree of symmetry are said to belong to the Cubic or Tesseral System. |
2. Mensuration. Of three dimensions; solid; relating to solid content; esp. used with a unit of length, to express the content or volume of a cube whose edge is that unit, as a cubic foot.
| 1660 Boyle New Exp. Phys. Mech. xvii. 116 We may..define, either in weight or cubick measures the Cylinder of Quick-silver. 1751 C. Labelye Westm. Br. 87 The two Middle Piers..contain full 3000 cubic Feet. 1812–6 Playfair Nat. Phil. (1819) I. 13 The weight of a cubic inch of water. 1869 E. A. Parkes Pract. Hygiene (ed. 3) 125 For sick persons the cubic space should be more than for healthy persons. |
3. Arith., Alg., etc. Relating to or involving the cube or third power of a quantity; of three dimensions, of the third degree.
As † cubic number = cube number; † cubic root = cube root; cubic equation, an equation of the third degree; cubic curve, a curve represented by an equation of the third degree.
| 1551 Recorde Pathw. Knowl. ii. Pref., Extraction of rootes both square and cubike. 1594 Blundevil Exerc. i. xxvi, (ed. 7) 59 A Table containing both the square numbers and Cubique numbers of every Root. 1727–51 Chambers Cycl., Cubic equation is an equation wherein the unknown quantity is of three dimensions. Ibid. s.v. Curve, One [curve] commonly called the cubic parabola. 1885 Watson & Burbury Math. Th. Electr. & Magn. I. 179 The system leads to a cubic equation in ε. |
B. n. (ellipt. use of the adj.).
1. Math. a. A cubic expression or equation. b. A cubic curve.
| 1799 Wilson in Phil. Trans. LXXXIX. 301 The rest produce cubics, or cubic-formed sixth powers. 1806 Robertson Ibid. XCVI. 310 A cubic, or an equation of three dimensions. 1882 in Athenæum 15 Apr. 479/3 On Polygons circumscribed about a Cuspidal Cubic. |
2. A cubist painting. rare.
| 1924 Galsworthy White Monkey i. ii. 14 The cubic called ‘Still Life’. |