belongyoudaoicibaDictYouDict[belong 词源字典]
belong: [14] Old English had a verb langian, meaning ‘pertain to’. It had no immediate connection with the other Old English verb langian, modern English long, ‘desire’, but came from the Old English adjective gelang ‘pertaining, belonging’ (although ultimately this gelang and the modern English adjective and verb long come from the same Germanic source, *langgaz). The intensive prefix be- was added in the 14th century.
=> long[belong etymology, belong origin, 英语词源]
belong (v.)youdaoicibaDictYouDict
mid-14c., "to go along with, properly relate to," from be- intensive prefix, + longen "to go," from Old English langian "pertain to, to go along with," which is of unknown origin. Senses of "be the property of" and "be a member of" first recorded late 14c. Cognate with Middle Dutch belanghen, Dutch belangen, German belangen. Replaced earlier Old English gelang, with completive prefix ge-.