We don't have synonyms for rowel yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are vowel, towel and trowel.
"1819, The deep and sharp rowels with which Ivanhoe's heels were now armed, began to make the worthy Prior repent of his courtesy -- Walter Scott, Ivanhoe"
°To use a rowel on something, especially to drain fluid.
"1819, The deep and sharp rowels with which Ivanhoe's heels were now armed, began to make the worthy Prior repent of his courtesy -- Walter Scott, Ivanhoe"
°To use a rowel on something, especially to drain fluid.