六角ナット

A nut is a threaded fastener that pairs with a bolt or stud to clamp parts together.

Turning the nut onto the thread draws the joint tight and holds it by the clamping force; lock nuts add a feature that resists loosening under vibration.

Nuts are used with bolts and studs across the vehicle. The correct nut matches the thread size, strength grade, and the type specified for the joint.