you got yourselves two distinct words with unique spellings there folks!

ferrule \fer-ul\ noun [alter. of ME virole, fr. MF, fr. L viriola, dim. of viria bracelet, of Celtic origin; akin to OIr fiar oblique] (1611)
1 : a ring or cap usu. of metal put around a slender shaft (as a cane or a tool handle) to strengthen it or prevent splitting
2 : a usu. metal sleeve used esp. for joining or binding one part to another (as pipe sections or the bristles and handle of a brush)
ferruled adjective

ferule \fer-ul\ also ferula \fer-(y)e-le\ noun [L ferula giant fennel, ferule] (1580)
1 : an instrument (as a flat piece of wood like a ruler) used to punish children
2 : school discipline


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