Cadillac converter

Meanings

1. Synonym of catalytic converter (“chamber containing a finely divided platinum catalyst in which carbon monoxide and hydrocarbons from vehicle exhaust are oxidized to carbon dioxide”).

Etymology

From the similarity between catalytic and Cadillac (“brand of luxury automobile”), probably originally a mondegreen (“error arising from the mishearing of a phrase”) and used humorously to allude to the high cost of catalytic converters.