a colourless or white mineral sometimes tinted by impurities, found in beds as an evaporite. It is used in the manufacture of plaster of Paris, cement, paint, school chalk, glass, and fertilizer. Composition: hydrated calcium sulphate. Formula: CaSO4.2H2O. Crystal structure: monoclinic
WordReference Random House Learner's Dictionary of American English © 2025
gyp•sum /ˈdʒɪpsəm/USA pronunciation
n. [uncountable]
WordReference Random House Unabridged Dictionary of American English © 2025- Mineralogya soft white mineral, a form of calcium, used to make plaster of Paris and as a fertilizer.
gyp•sum
( jip′səm),USA pronunciation n.
- Mineralogya very common mineral, hydrated calcium sulfate, CaSO4·2H2O, 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.
- Greek gýpsos chalk, gypsum
- Latin: chalk
- 1640–50
Collins Concise English Dictionary © HarperCollins Publishers::
'gypsum' also found in these entries (note: many are not synonyms or translations):
Gyprock
- Mohs scale
- Sheetrock
- alabaster
- calcium
- cap rock
- evaporite
- gesso
- gypseous
- gypsiferous
- gypsum board
- gypsum plaster
- hardwall
- land plaster
- parget
- plaster
- plaster of Paris
- plasterboard
- poudrette
- saltpan
- satin spar
- selenite
- spar
- sulphur
- terra alba
- tile
- wallboard