D defs.my
Entry 1 sense Webster, 1913

Gypsum

/(jĭp"sŭm)/ · Gyp·sum · IPA /ˈd͡ʒɪp.səm/
01 n. A mineral consisting of the hydrous sulphate of lime (calcium). When calcined, it forms plaster of Paris. Selenite is a transparent, cryst…
  1. 1.
    A mineral consisting of the hydrous sulphate of lime (calcium). When calcined, it forms plaster of Paris. Selenite is a transparent, crystalline variety; alabaster, a fine, white, massive variety.(Min.)