tetragonal, a. (n.)
(tɪˈtrægənəl)
Also (in sense 4) -el.
[f. prec. + -al1. So mod.F. tétragonal.]
A. adj.
1. Of or pertaining to a tetragon; having four angles; quadrangular.
| 1571 Digges Pantom. iv. T j b, When any equiangle triangle, square, or Pentagonum is..described within a circle,..their sides are called the trigonall, tetragonall and pentagonall Cordes of that circle. 1667 Phil. Trans. II. 627 Two Tetragonal Prismes of Tendons. 1874 Coues Birds N.W. 592 An elongated pyramid with a tetragonal base. |
2. Bot. and Zool. Quadrangular in section, like a ‘square’ rod; tetraquetrous.
| 1753 Chambers Cycl. Supp. s.v. Leaf, A leaf that has, instead of three ribs or edges, four or five, is..called tetragonal, pentagonal, &c. 1853 Royle Mat. Med. (ed. 2) 641 Norway Spruce Fir. Leaves scattered, tetragonal. 1875 C. C. Blake Zool. 109 The bill is elongate,..tetragonal, and acuminate. |
† 3. Astrol. = quartile a., quadrate a. 2. Obs.
| 1646 Sir T. Browne Pseud. Ep. iv. xii. 213 Reckoning on unto the seventh day, the Moone will be in a Tetragonall or Quadrate aspect, that is, 4. signes removed from that wherein the disease began. |
4. Her. Represented as quadrangular: see quot.
| c 1828 Berry Encycl. Her. I. Gloss., Tetragonel Pyramids, piles are generally considered to represent wedges,..they are sometimes borne..square, in which latter case they may be termed square piles, or tetragonel pyramids reversed. 1889 Elvin Dict. Her., Tetragonal Pyramids. |
5. Cryst. Applied to a system of crystallization in which the three axes are at right angles, the two lateral axes being equal, and the vertical of a different length. Also applied to (the structure and symmetry of) substances crystallizing in this system.
| 1868 Dana Min. (ed. 5) Introd. 21 Crystallography..systems of crystallization... Having only the lateral axes equal. The Tetragonal and Hexagonal. 1878 Gurney Crystallogr. 38 If four symmetral planes only intersect in the same straight line it is called an axis of tetragonal symmetry. 1879 Rutley Stud. Rocks ix. 77 Crystals belonging to the tetragonal and hexagonal systems are singly refractive when viewed in the direction of the principal crystallographic axis. 1886 [see grey tin s.v. grey, gray a. 8 c]. 1912 Dana's Man. Mineral. (ed. 13) 36 The cross section of a crystal when viewed in the direction of the axis of tetragonal symmetry consists usually of a square or a truncated square. 1937 A. F. Rogers Introd. Study Minerals (ed. 3) i. 67 Interfacial angles in the prism zone are the same for corresponding faces of all tetragonal crystals. 1973 H. D. Megaw Crystal Structures xii. 307 Several other modifications of the spinel structure have been reported. Cr2CuO4 has a different tetragonal structure, with approximately the same unit cell as Cr2NiO4. |
† B. n. = tetragon 1. Obs. rare—1.
| 1684 tr. Agrippa's Van. Arts To Rdr., The intricate Geometrician will imprison me in his Triangles and Tetragonals. |
Hence teˈtragonally adv., in a tetragonal manner or form; teˈtragonalness.
| 1727 Bailey vol. II, Tetragonalness, the having four Corners, Squareness. 1888 Cassell's Encycl. Dict., Tetragonally. 1963 Q. Jrnl. Geol. Soc. CXIX. 326 Tetragonally symmetrical flattened pumice lapilli. 1966 Phillips & Williams Inorg. Chem. II. xxv. 248 CuF2 has a tetragonally-distorted rutile structure. |