vitr(o)- Also vitri-.
[Latin vitrum, glass.]
The adjective vitreous refers to some substance like glass in appearance or physical properties; the vitreous humour is the transparent tissue filling the eyeball behind the lens, hence vitrectomy (Greek ektomē, excision) for the surgical operation of removing or replacing it. Vitrophyre (German Porphyr, porphyry) is a type of igneous rock containing embedded glassy particles; vitrification is the conversion of a material into a glass-like substance, typically through heat. The Latin phrase in vitro (literally ‘in glass’) refers to processes taking place in a test tube, culture dish, or elsewhere outside a living organism, the opposite of in vivo.