I. ˈjipsəm noun
( -s )
Usage: often attributive
Etymology: Latin gypsum, gypsus, from Greek gypsos chalk, gypsum, cement, of Semitic origin; akin to Arabic jibs plaster, mortar
1. : a widely distributed mineral CaSO 4 .2H 2 O consisting of hydrous calcium sulfate that is colorless when pure, occurs massive or in the form of monoclinic crystals that easily split into folia, and is used chiefly as a soil amendment, as a retarder in portland cement, and in making plaster of Paris (hardness 2, specific gravity 2.31-2.32)
2. : plasterboard
gypsum lath
gypsum sheathing
gypsum wallboard
II. transitive verb
( -ed/-ing/-s )
: to treat (as soil or water) with gypsum