unfold (v.)youdaoicibaDictYouDict[unfold 词源字典]
Old English unfealdan, "to open or unwrap the folds of," also figuratively, "to disclose, reveal, explain," from un- (2) "opposite of" + fold (v.). Similar formation in Middle Dutch ontvouden, German entfalten. Intransitive sense is attested from late 14c. Related: Unfolded; unfolding.[unfold etymology, unfold origin, 英语词源]