A prusik knot is a friction hitch tied with a thin loop of cord around a climbing rope. When weighted it grips the rope and holds; when the load is released it slides freely by hand. This lets climbers ascend a rope, back up a rappel, or build a hauling system for crevasse rescue.
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 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).
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.
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.
Top-rope climbing is a style in which the rope runs from the climber up to an anchor at the top of the route and back down to the belayer. Because the rope is always anchored above, a slip results in only a short fall, making it the safest and most common way for beginners to start climbing.
A dyno, short for dynamic move, is a climbing move in which you spring off the wall to reach a hold too far away to grab statically. At full extension all four limbs may briefly leave the rock before your hands latch the target hold. It trades control for reach and is a signature move of modern bouldering.
A heel hook is a climbing technique where you place your heel on a hold and pull with your leg, using it almost like a third hand. It lets you take weight off your arms, stay close to the wall on steep terrain, and lock into position on overhangs, aretes, and around bulges.
The Yosemite Decimal System (YDS) is the rating scale used in the United States to describe how difficult terrain is to travel, from flat walking to hard rock climbing. It runs through five classes; Class 5 covers technical roped climbing and is subdivided with decimals from 5.0 up to 5.15 for increasing difficulty.
A redpoint is a successful lead climb of a route from bottom to top without falling or resting on the rope, after having practiced it. It is the standard benchmark for 'sending' a hard route and contrasts with an onsight (no prior knowledge) and a flash (first try, but with beta).