Crossbow Glossary

Plain-English definitions of the terms you will meet when researching crossbows, each linked to the guides that use them.

Anatomy

The parts of a crossbow and how they fit together.

Limb: One of the two flexing arms at the front of the crossbow that store energy when drawn.
Riser: The central frame at the front of the crossbow to which the limbs are mounted.
Rail: The channel or track along the top of the stock that guides the bolt and string.
Axle-to-Axle: The distance between the limb axles or cam axles at the front of the crossbow.
Reverse-Draw: A crossbow layout with the limbs angled back toward the shooter rather than forward.
Trigger System: The mechanism that holds the string when cocked and releases it when the trigger is pulled.

How the two main designs differ.

Compound Crossbow: A crossbow that uses cams and cables on the limbs to store and release energy.
Recurve Crossbow: A crossbow whose limbs curve away from the shooter and carry the string directly, without cams.

The numbers on the box, and how to read them.

Draw Weight: The force, in pounds, needed to draw the string to its cocked position.
Power Stroke: The distance the string travels from its cocked position to its resting position.
FPS (Feet Per Second): The speed of a bolt as it leaves the crossbow, measured in feet per second.
Kinetic Energy: The energy a bolt carries, usually expressed in foot-pounds, derived from its weight and speed.

Aiming, adjusting and measuring accuracy.

Scope: An optical sight mounted on the crossbow with a reticle used to aim.
MOA (Minute of Angle): An angular unit used for scope adjustments and accuracy; about 1 inch at 100 yards.
Eye Relief: The distance between the rear lens of a scope and the shooter’s eye that gives a full sight picture.

What you shoot, and how it is balanced.

Bolt: The projectile a crossbow shoots; often used interchangeably with arrow.
Nock: The rear end of a bolt that engages the string.
FOC (Front of Center): The percentage of a bolt’s weight that sits ahead of its midpoint.
Broadhead: A bladed bolt tip designed for hunting, as opposed to a field point used for practice.

Cocking and the mistakes that damage crossbows.

Cocking Aid: A rope or crank device that reduces the effort needed to draw the string.
Dry Fire: Releasing the string without a bolt loaded, which can seriously damage a crossbow.