Rowel

(rou'el), n. [O. Fr. roele, roue(le, N. Fr. rouelle, equivalent to Lat. rotula, a little wheel, dim. of roe, roue, Lat. rota, a wheel.]

1. The little wheel of a spur, formed with sharp points. “With sounding whip and rowels dyed in blood.” Cooper.
2. A little flat ring or wheel of plate or iron on horses’ bits.

The iron rowels into frothy foam he bit. Spencer. 3. (Far.) A roll of hair or silk, passed through the flesh of horses, answering to a seton in surgery.