a. Zool. [f. L. turbin-em (see TURBO) + -OID.] Resembling the genus Turbo or family Turbinidæ of gastropod mollusks (esp. those of tropical and subtropical seas) characterized by a thick top-shaped shell with a rounded opening closed by a calcareous operculum.
1861. P. P. Carpenter, in Rep. Smithsonian Instit., 1860, 213. Fossils of Turbinoid form.
1879. W. B. Carpenter, in Encycl. Brit., IX. 379/2. The type of the second group is the almost universally diffused Rotalia, in which the chambers are disposed in a turbinoid spire.
