D.A.youdaoicibaDictYouDict[D.A. 词源字典]
American English initialism (acronym) for district attorney from 1934; for duck's ass haircut (or, as OED would have it, duck's arse), from 1951. The haircut so called for the shape at the back of the head.[D.A. etymology, D.A. origin, 英语词源]