Definitions of vitreous:

• adjective:   relating to or resembling or derived from or containing glass

  Example: "Vitreous rocks"

• adjective:   of or relating to or constituting the vitreous humor of the eye

  Example: "The vitreous chamber"

• adjective:   (of ceramics) having the surface made shiny and nonporous by fusing a vitreous solution to it

  Example: "Hard vitreous china used for plumbing fixtures"