Finn (n.)youdaoicibaDictYouDict[Finn 词源字典]
Old English finnas, from Old Norse finnr, the Norsemen's name for the Suomi. Some suggest a connection with fen. Attested in Tacitus as Fenni. Finlander in English is from 1727.[Finn etymology, Finn origin, 英语词源]
mainland (n.)youdaoicibaDictYouDict
c. 1400, from main (adj.) + land (n.). Usually referring to continuous bodies of land and not islands or peninsulas. Related: Mainlander.
RhinelandyoudaoicibaDictYouDict
1670s, from German Rheinland; see Rhine + land (n.). Related: Rheinlander.