What is the meaning of Rowel?

The small spiked wheel on the end of a spur.

A little flat ring or wheel on a horse's bit.

A roll of hair, silk, etc., passed through the flesh of a horse in the manner of a seton in human surgery.

To use a rowel on (something), especially to drain fluid.

To fit with spurs.

To apply the spur to.

To incite; to goad.

Source: wiktionary.org