1. A colorless deliquescent powder, Ca(H₂PO₄)₂, used in baking powders, as a plant food, as a plastic stabilizer, and in glass.
2. A white crystalline powder, CaHPO₄, used as an animal food, as a plastic stabilizer, and in glass and toothpaste.
3. A white amorphous powder, Ca₃(PO₄)₂, used in ceramics, rubber, fertilizers, and plastic stabilizers and as a food supplement.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.