ferule (n.)youdaoicibaDictYouDict[ferule 词源字典]
"rod or flat piece of wood for punishing children," 1590s, earlier "giant fennel" (early 15c.), from Middle English ferula "fennel plant" (late 14c.), from Latin ferula "reed, whip, rod, staff; fennel plant or stalk" (fennel stalks were used for administering flogging punishment in ancient Roman times) probably related to festuca "stalk, straw, rod."[ferule etymology, ferule origin, 英语词源]