Dictionary
gyp•sum
Pronunciation: ( jip'sum), [key]—
n.
a very common mineral, hydrated calcium sulfate, CaSO
4·2H
2O, occurring in crystals and in masses, soft enough to be scratched by the fingernail: used to make plaster of Paris, as an ornamental material, as a fertilizer, etc.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.