UNDERPAN Meaning of UNDERPAN in English ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ nounEtymology: under (III) + pan : a protective metal covering fitting under the engine, clutch, and transmission case of an automobile Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012