inner (adj.)youdaoicibaDictYouDict[inner 词源字典]
c. 1400, from Old English inra, comparative of inne (adv.) "inside" (see in). Similar formation in Old High German innaro, German inner. An unusual evolution for a comparative, it has not been used with than since Middle English. Inner tube in the pneumatic tire sense is from 1894. Inner city, in reference to poverty and crime, is attested from 1968.[inner etymology, inner origin, 英语词源]