Nock, arrow
plastic part glued or pressed into the back of an arrow that accepts the bowstring

Nock, bow
a term sometimes used to describe the string groves on each end of the bow

Nock, cushion
used as a barrier between the string nock and a release to lessen the pinch at full draw

Nock set
A small brass attachment added to the string to mark the nocking point.

Nock, self
grove that is manually cut in the back of primitive arrows to accept the bowstring

Nock, string
various material put on bow string to permanently mark the nocking point

Nocking pliers
used to put on brass string nocks

Nocking point
exact spot on bowstring where the arrow is placed before being shot

Nut

The part of the release mechanism of a crossbow where the string sits when the crossbow is drawn