Webster's Revised Unabridged Dictionary · 1913

Rowel

Rowel , noun

[Old French roele, rouele, properly, a little wheel, French rouelle collop, slice, Late Latin rotella a little wheel, dim. of Latin rota a wheel. See Roll, and compare Rota.]

1.
The little wheel of a spur, with sharp points.
With sounding whip, and rowels dyed in blood. — Cowper
2.
A little flat ring or wheel on horses' bits.
The iron rowels into frothy foam he bit. — Spenser
3.
(Farriery) A roll of hair, silk, etc., passed through the flesh of horses, answering to a seton in human surgery.

Rowel , transitive verb

(Farriery) To insert a rowel, or roll of hair or silk, into (as the flesh of a horse). — Mortimer