discolith
/ˈdɪskə(ʊ)lɪθ/Biology
noun
Any coccolith with a more or less discoid shape, often with a thickened or elevated rim surrounding a central area which may be perforated.
Origin
Late 19th century; earliest use found in Quarterly Journal of Microscopical Science. From disco- + -lith, after scientific Latin Discolithus.