sb. and a. Also 7–9 sphæroid, 8 spheroide. [ad. L. sphæroīdēs, ad. Gr. σφαιροειδής, f. σφαῖρα ball: see -OID. So F. sphéroïde (1556), It. sferoide, Sp. and Pg. esferoide.]
A. sb. A body approaching in shape to a sphere, esp. one formed by the revolution of an ellipse about one of its axes. Oblate, prolate spheroid: see the adjs.
1664. Barrow, in Rigaud, Corr. Sci. Men (1841), II. 39. Were I to compute the portions of a sphere or spheroid, I should only use these rules, out of Archimedes.
1698. Keill, Exam. Th. Earth (1734), 95. After the fashion of a broad spheroid which is generated by the rotation of a semi Ellipsis round its lesser Axis.
1777. Phil. Trans., LVII. 285. Conceive now a spherical surface … to be carried about with the revolving spheroid.
1829. Chapters Phys. Sci., 41. In all cases, the centre of gravity tends towards the centre of the terrestrial spheroid, or to a point very near to it.
1854. Murchison, Siluria, vi. 134. [Mudstone] has a tendency to run into large spheroids.
1881. Le Conte, Sight, 52. The form of a perfect eye is that of a spheroid of revolution about the optic axis.
B. adj. = SPHEROIDAL a.
1767. Murdoch, in Phil. Trans., LVIII. 32. As no two measurements … make the earth of the same spheroid figure.
1875. Cooke, Fungi, 62. Afterwards small sphæroid projections appear at certain points on the mycelium.
1884. Jefferies, Red Deer, iii. 42. The spheroid form concentrates more substance in a given measurement than any other.
