Mountaineering Vocabulary in English — 20 Essential Terms

A crevasse is any deep crack or split in a glacier, formed as the ice moves and stresses over uneven ground. Crevasses can appear anywhere on a glacier and are especially dangerous when hidden under a thin bridge of snow. A bergschrund is a particular kind of crevasse: it forms at the very top of a glacier, where the moving ice pulls away from the steeper, more stationary ice or rock above. The bergschrund often marks the boundary between the glacier and the headwall, and crossing it can be one of the hardest and most exposed parts of an alpine climb.

Acclimatisation is the process by which the body slowly adapts to the reduced oxygen found at high altitude. As you climb higher, the air contains less oxygen, and without time to adjust, climbers risk altitude sickness, which can progress to dangerous swelling of the lungs or brain. Acclimatisation is usually achieved by the principle of ‘climb high, sleep low’: climbers ascend to a higher point during the day, then return to a lower camp to sleep, repeating this over several days so the body gradually produces more red blood cells and adjusts. Skipping or rushing acclimatisation is one of the most common and serious mistakes on a big mountain.

An ice axe is one of the most important and versatile tools in mountaineering. Its head has a pointed pick on one side and a flat adze on the other, with a spike at the base of the shaft. Climbers use it for balance and support when walking on snow slopes, for cutting or kicking steps, and above all for self-arrest — the crucial technique of digging the pick into the snow to stop a slide if they fall. In steeper ice climbing, a pair of shorter, more curved technical axes is used to pull directly up the ice. Knowing how to use an ice axe to self-arrest is a fundamental safety skill.

Although both are features of mountain terrain, a col and a couloir are very different. A col is the lowest point on a ridge between two peaks — a kind of natural saddle or pass that climbers often use to cross from one side of a mountain to the other or as a resting point. A couloir, by contrast, is a steep, narrow gully running up the side of a mountain, frequently filled with snow or ice. Couloirs can offer an efficient climbing line but are dangerous because they channel falling rocks and avalanches, so they are often climbed early in the day when everything is still frozen in place.

A cornice and a serac are two of the classic objective dangers in the mountains — hazards that exist regardless of a climber's skill. A cornice is an overhanging lip of wind-blown snow that builds up along a ridge or cliff edge; it can look like solid ground but may break away under a climber's weight, dropping them over the edge, so climbers must keep well back from it. A serac is a huge block or tower of glacial ice that can topple or collapse without warning. Because there is no way to know exactly when a serac will fall, climbers try to spend as little time as possible beneath them, often moving through such zones quickly and in the cold of early morning.

A whiteout occurs when cloud, fog, or blowing snow removes all visual contrast, so the snow, the sky, and the horizon blend into a single featureless white. In these conditions climbers lose their sense of distance, direction, and even which way is up or down a slope. This makes navigation extremely difficult and dangerous, as it becomes easy to walk off a cliff, blunder onto a cornice, or become hopelessly lost. To cope with a whiteout, mountaineers rely on a compass, a map, an altimeter, or GPS, and often the safest decision is to stop, shelter, and wait for visibility to improve rather than risk a fatal mistake.

A summit push is the final, all-out effort to reach the top of a mountain. On a major peak, climbers do not simply walk to the summit; instead, after days or weeks of carrying loads, acclimatising, and resting, they wait at a high camp for a suitable weather window. The summit push is then made, often starting in the middle of the night so that climbers can reach the top and return to safety before the afternoon brings worse weather or softening snow. It is usually the most physically and mentally demanding part of an entire expedition, made in the thin air of extreme altitude.

Both frostbite and altitude sickness are constant threats high on a mountain, and climbers manage them with care. To prevent frostbite, they wear well-insulated boots, layered gloves or mittens, and face protection, keep moving to maintain circulation, stay hydrated, and watch each other for the pale, numb skin that signals early freezing. To guard against altitude sickness, they acclimatise gradually, ascend at a measured pace, drink plenty of fluids, and descend at once if symptoms become serious, since going down is the most reliable cure. On the highest peaks, climbers may also use supplementary oxygen to reduce the strain of the thin air.

Base camp is the main camp set up at the foot of a mountain and acts as the heart of an expedition. It is where supplies, food, and equipment are stored, where climbers rest and recover between rotations to the higher camps, and where they wait for good weather before a summit attempt. Base camp is usually located at an altitude where the body can recover reasonably well, so climbers descend to it to regain strength after spending time higher up. It also serves as a communications and medical hub, and on busy mountains it can grow into a small temporary village of tents.

The most effective approach is to encounter the words in the context of real journeys and landscapes. Reading English-language expedition accounts, climbing books, and trip reports lets you see terms like crevasse, col, serac, and summit push describing actual situations, which makes their meaning vivid and memorable. Looking at photographs and diagrams of mountains and labelling the features — the ridge, the couloir, the moraine — also helps fix the words in your mind. Practise the 20 terms on this page with Flash Cards on LexFizz, then test yourself with the Matching Pairs exercise to make sure each piece of gear, landform, and condition is firmly linked to its meaning.