coccolith: Meaning and Definition of

coc•co•lith

Pronunciation: (kok'u-lith"), [key]
— n.
  1. a microscopic calcareous disk or ring making up part of the covering of certain marine plankton and forming much of the content of chalk rocks.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.