sur- (1)youdaoicibaDictYouDict[sur- 词源字典]
word-forming element meaning "over, above, beyond, in addition," especially in words from Anglo-French and Old French, from Old French sour-, sor-, sur-, from Latin super (see super-).[sur- etymology, sur- origin, 英语词源]
sur- (2)youdaoicibaDictYouDict
assimilated form of sub- before -r-.