ergo (conj.)youdaoicibaDictYouDict[ergo 词源字典]
c. 1400, from Latin ergo "therefore, in consequence of," possibly from *ex rogo "from the direction," from ex "out of" (see ex-) + root of regere "to guide" (see regal). Used in logic to introduce the conclusion of a complete and necessary syllogism.[ergo etymology, ergo origin, 英语词源]