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Trade name, from the names of Johns Hopkins University and the University of California, where the research was carried out, + -ite.
Etymology from Wiktionary, CC BY-SA 4.0.
Hopcalite
Today it means: Any of various mixtures of mainly oxides of copper and manganese, used as catalysts for the conversion of carbon monoxide to carbon dioxide when exposed to the oxygen in the air at room temperature. Full definition →