PyrexPronunciation: /ˈpʌɪrɛks/Translate Pyrex | into Italian | into Spanish Definition of Pyrex noun [mass noun, usually as modifier] trademark a hard heat-resistant type of glass, typically used for ovenware:a set of Pyrex dishesOrigin: early 20th century: an invented wordPyrex in other Oxford dictionaries Definition of Pyrex in the US English dictionary