Crossbow Authority

Crossbow glossary

What Is Nock?

Nock: The rear end of a bolt that engages the string.

By Marisol Vega, Senior Outdoor Equipment Writer & Research Editor. Manufacturer figures vary; check your crossbow's manual.

The nock holds the bolt on the string. Types include flat, half-moon and lighted nocks, and they are not interchangeable across all crossbows. Use the nock type specified by your crossbow manufacturer.

A damaged or loose nock is a common cause of inconsistent flight and should be replaced.

Why Nock matters

The nock is a small part with a big job: it holds the bolt on the string until release. A nock that fits poorly can cause erratic flight, or in the worst case can fail on release.

Nock types vary between crossbow brands, and not all are interchangeable.

How to read it on a spec sheet

  • Check the nock type your crossbow requires (flat, half-moon or lighted) and whether the string has a compatible feature.
  • Look at how snugly the bolt sits on the string. It should hold in place without force.

Common mistakes

  • Mixing nock types with a crossbow that is not designed for them.
  • Ignoring a cracked or worn nock because the bolt still seems to seat.

Frequently asked questions

What is a lighted nock?

A nock with a small LED that lights on release, making the bolt’s flight and impact easier to see. Check the legality in your area, as rules vary.

How do I know my nock fits?

It should match the crossbow manufacturer’s specification and hold the bolt securely on the string without being forced on.

See it in our reviews

Read more in our guides

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Definitions are general information. Always follow your crossbow manufacturer's manual, and verify local laws with the relevant authority.