progyoudaoicibaDictYouDict[prog 词源字典]
1958, colloquial shortening of progressive (q.v.). Earlier it was British student slang for proctor (1890) and earlier still a cant word for "food, provisions" (1650s), perhaps from verb prog "to poke about" (1610s), of unknown origin, perhaps related to prod (v.). Related: Progged; progging.[prog etymology, prog origin, 英语词源]