Meaning

noun a borosilicate glass with a low coefficient of expansion; used for heat-resistant glassware in cooking and chemistry

originFrom pie + r + -ex. First manufactured by the Corning Glassware Factory in 1915. * 1957, Letter from the Corning Glassware Factory: *: "We had a number of prior trademarks ending in the letters ex. One of the first commercial products to be sold under the new mark was a pie plate, and in the interests of euphonism the letter "r" was inserted between pie and ex, and the whole thing condensed to…

Etymology from Wiktionary, CC BY-SA 3.0