Smearing is a footwork technique where you press the sole of your climbing shoe flat against the rock to grip through friction, rather than standing on a defined hold. It's essential on slabs and featureless faces, relying on sticky rubber, body position, and trusting your feet on seemingly blank rock.
Edging is a footwork technique where you stand on a small hold using the stiff edge of your climbing shoe, usually the inside edge near the big toe. It gives precise, powerful purchase on tiny ledges and crystals, and works best on vertical to slightly overhanging rock with defined footholds.
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.
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 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).
Rappelling, also called abseiling, is the technique of descending a rope in a controlled way using friction from a belay or rappel device. Climbers use it to get down from routes and anchors. Because it depends entirely on the system being built correctly, rappelling is a leading cause of climbing accidents and demands rigorous checks.
Belaying is the technique of managing a climbing rope to protect a climber from falling. A belayer uses a belay device and the friction of the rope to hold a fall, lower the climber, and feed or take in slack as the climber moves. It is the core safety system of roped climbing.