In each of the tips of horn is a notch for the string called "the nock."
Scarcely had Johnny stepped back to nock an arrow, than the other saw him.
This is the application of the nock of the arrow to its proper place on the string.
In each of the tips of the horns is a notch for the string, called the nock.
He thought seriously for several moments, then telepathed Nock.