Definition of "Vitreous" :

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

"Hard vitreous china used for plumbing fixtures."

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

"Vitreous rocks."

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

"The vitreous chamber."