'Ground glass' definitions:

Definition of 'ground glass'

From: WordNet
noun
Glass that diffuses light due to a rough surface produced by abrasion or etching
noun
Particulate glass made by grinding and used as an abrasive

Definition of 'Ground glass'

From: GCIDE
  • ground \ground\, imp. & p. p. of Grind. [1913 Webster]
  • ground cock, a cock, the plug of which is ground into its seat, as distinguished from a compression cock. --Knight.
  • Ground glass, glass the transparency of which has been destroyed by having its surface roughened by grinding.
  • Ground joint, a close joint made by grinding together two pieces, as of metal with emery and oil, or of glass with fine sand and water. [1913 Webster]