A dynamic rope is a climbing rope engineered to stretch and absorb the energy of a fall, reducing the force on the climber, gear, and belayer. Its stretchy kernmantle construction — a core sheathed in a woven cover — makes it the standard rope for lead climbing and top-roping, distinct from low-stretch static rope used for rappelling and hauling.
An ATC is a lightweight tube-style belay device. The name comes from Black Diamond's 'Air Traffic Controller' and is now used generically for similar tubes. The rope bends through a slot and against a carabiner to create friction for belaying and rappelling. Simple and versatile, it works with one or two ropes and has no moving parts.
A nut, also called a stopper or chock, is a passive piece of trad protection — a tapered metal wedge on a wire cable that a climber slots into a constriction in a crack so it jams when pulled downward. Nuts are light, cheap, and reliable in tapering cracks, forming the foundation of a traditional rack.
A cam, short for spring-loaded camming device (SLCD), is an active piece of climbing protection that a trad climber slots into a crack. Pulling a trigger retracts the spring-loaded lobes; releasing them lets the lobes expand to grip the crack walls. Cams place quickly and hold well in parallel-sided cracks where passive gear can't.
A crash pad is a portable foam mattress that boulderers place beneath a climb to cushion falls. It combines a stiff top layer of closed-cell foam that spreads impact with a softer open-cell base that absorbs it, and folds with backpack straps so it can be carried to the rock.
A chalk bag is a small pouch worn at the waist that holds climbing chalk. A climber dips a hand in mid-route to coat the fingers with magnesium carbonate, which absorbs sweat and improves grip on holds. Most have a fleece lining, a drawcord closure, and a stiffened rim for easy one-handed dipping.
A locking carabiner is a metal connector whose gate can be locked shut so it cannot open accidentally. Climbers use it for critical connections — attaching a belay device, clipping into an anchor, or rappelling — where an open gate could be catastrophic. Locks are either manual (screw) or automatic (twist or magnetic).
Approach shoes are a hybrid between hiking shoes and climbing shoes, built for the rough, rocky walk to the base of a climb. They use sticky climbing-style rubber and a precise toe so you can scramble and edge on rock, while keeping enough cushioning and tread to hike comfortably.
The GriGri is an assisted-braking belay device made by Petzl that uses a camming mechanism to help lock the rope when a climber falls. Widely used in sport climbing and gyms, it adds a margin of safety over tube-style devices but still requires a hand on the brake strand at all times.
A belay device is a piece of equipment that creates friction on the climbing rope so a belayer can hold a fall, lower a climber, and manage slack with controlled effort. Designs range from simple tube-style devices to assisted-braking devices that help lock the rope automatically.