in-line skate [1]
Reinforced boot with four wheels placed in a straight line; it is used to move around on a hard, relatively smooth surface.
truck 
Device that connects the wheels to the boot.
axle 
Wheel’s rotational axis that connects it to the frame.
wheel 
Round object that turns on an axis so the skate can move backward or forward.
heel stop 
Rubber pad at the back of the skate that enables the skater to slow down or stop.
boot 
Ankle boot that protects the foot and ankle; depending on the intended use, it can be soft, semisoft or hard (shell).
adjusting buckle 
Clip made up of a metal ring that fits into an adjusting catch to tighten the boot.
upper shell 
Part of the boot that covers the lower part of the leg; it is usually hinged at the ankle.
inner boot 
Cushioned, often removable lining that is designed for greater comfort inside the boot.