calcium carbonaten. A colorless or white crystalline compound, CaCO3, occurring naturally as chalk, limestone, marble, and other forms and used in a wide variety of manufactured products including commercial chalk, Portland cement, medicines, and dentifrices.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.calcium carbonate n (Elements & Compounds) a white crystalline salt occurring in limestone, chalk, marble, calcite, coral, and pearl: used in the production of lime and cement. Formula: CaCO3 Collins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014cal?cium car?bonate n. a white powder, CaCO3, occurring in nature as calcite, chalk, etc., used in dentifrices and polishes and in manufacturing lime and cement. [1870?75] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.calcium carbonate A white or colorless crystalline compound, CaCO3, occurring naturally in chalk, limestone, and marble. It is used to make toothpaste, white paint, and cleaning powder.The American Heritage® Student Science Dictionary, Second Edition. Copyright © 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.