| Term | Definition |
|---|
| Ablation | A general term for the loss of ice and snow from a glacier. |
| Abrasion | The grinding and scraping of a rock surface by the friction and impact of rock particles carried by water, wind, and ice. |
| Alpine glacier | A glacier confined to a mountain valley, which in most instances had previously been a stream valley. |
| Arète | A narrow, knifelike ridge separating two adjacent glaciated valleys. |
| Basal slip | A mechanism of glacial movement in which the ice mass slides over the surface below. |
| Calving | Wastage of a glacier that occurs when large pieces of ice break into the water. |
| Cirque | An amphitheater-shaped basin at the head of a glaciated valley produced by frost wedging and plucking. |
| Col | A pass between mountain valleys where the headwalls of two cirques intersect. |
| Crevasse | A deep crack in the brittle surface of a glacier. |
| Drumlin | A streamlined symmetrical hill composed of glacial till. The steep side of the hill faces the direction from which the ice advanced. |
| End moraine | A ridge of till marking a former position of the front of a glacier. |
| Esker | Sinuous ridge composed largely of sand and gravel deposited by a stream flowing in a tunnel beneath a glacier near its terminus. |
| Fiord | A steep-sided inlet of the sea formed when a glacial trough was partially submerged. |
| Firn | Granular recrystallized snow. A transitional stage between snow and glacial ice. |
| Glacial Budget | The balance, or lack of balance, between ice formation at the upper end of a glacier, and ice loss in the zone of wastage. |
| Glacial drift | An all-embracing term for sediments of glacial origin, no matter how, where, or in what shape they were deposited. |
| Glacial erratic | An ice-transported boulder that was not derived from the bedrock near its present site. |
| Glacial striations | Scratches and grooves on bedrock caused by glacial abrasion. |
| Glacial through | A mountain alley that has been widened, deepened, and straightened by a glacier. |
| Ground moraine | An undulating layer of till deposited as the ice front retreats. |
| Hanging valley | A tributary valley that enters a glacial trough at a considerable height above the floor of the trough. |
| Horn | A pyramid-like peak formed by glacial action in three or more cirques surrounding a mountain summit. |
| Ice cap | A mass of glacial ice covering a high upland or plateau and spreading out radially. |
| Ice sheet | A very large, thick mass of glacial ice flowing outward in all directions from one or more accumulation centers. |
| Kame | A steep-sided hill composed of sand and gravel, originating when sediment collected in openings in stagnant glacial ice. |
| Kame terrace | A narrow, terrace-like mass of stratified drift deposited between a glacier and an adjacent valley wall. |
| Kettle | Depression created when blocks of ice become lodged in glacial deposits and subsequently melt. |
| Lateral moraine | A ridge of till along the sides of a valley glacier composed primarily of debris that fell to the glacier from the valley walls. |
| Medial moraine | A ridge of till formed when lateral moraines from two coalescing alpine glaciers join. |
| Outwash plain | A relatively flat, gently sloping plain consisting of materials deposited by meltwater streams in front of the margin of an ice sheet. |
| Pater noster lakes | A chain of small lakes in a glacial trough that occupies basins created by glacial erosion. |
| Plastic flow | A type of glacial movement that occurs within the glacier, below a depth of approximately 50 meters, in which the ice is not fractured. |
| Plucking | The process by which pieces of bedrock are lifted out of place by a glacier. |
| Pluvial lake | A lake formed during a period of increased rainfall. |
| Recessional moraine | An end moraine formed as the ice front stagnated during glacial retreat. |
| Roche moutonnèe | An asymmetrical knob of bedrock formed when glacial abrasion smoothes the gentle slope facing the advancing ice sheet and plucking steepens the opposite side as the ice overrides the know. |
| Rock flour | Ground-up rock produced by the grinding effect of a glacier. |
| Snowline | The lower limit of perennial snow. |
| Stratified drift | Sediments deposited by glacial meltwater. |
| Surge | A period of rapid glacial advance. |
| Tarn | A small lake in a cirque. |
| Terminal moraine | The end moraine marking the farthest advance of a glacier. |
| Tillite | A rock formed when glacial till is lithified. |
| Truncated spur | Triangular-shaped cliff produced when a spur of land that extends into a valley is removed by the great erosional force of a valley glacier. |
| Valley glacier | A glacier confined to a mountain valley, which in most instances had previously been a stream valley. |
| Valley train | A relatively narrow body of stratified drift deposited on a valley floor by meltwater streams that issue from the terminus of an alpine glacier. |
| Zone of accumilation | The part of a glacier characterized by snow accumulation and ice formation. The outer limit of this zone is the snowline. |
| Zone of fracture | The upper portion of a glacier consisting of brittle ice. |
| Zone of wastage | The part of a glacier beyond the snowline where annually there is a net loss of ice. |
| Pleistocene epoch | An epoch of the Quaternary period beginning about 1.8 million years ago and ending about 10,000 years ago. Best known as a time of extensive continental glaciation. |
| Bajada | An apron of sediment along a mountain front created by the coalescence of alluvial fans. |
| Barchan dune | A solitary sand dune shaped like a crescent with its tips pointing downwind. |
| Blowout | A depression excavated by wind in easily eroded materials. |
| Cross-bedding | Structure in which relatively thin layers are inclined at an angle to the main bedding. Formed by currents of wind. |
| Deflation | The lifting and removal of loose material by wind. |
| Desert pavement | A layer of coarse pebbles and gravel created when wind removed the finer material. |
| Desertification | Ecosystem degradation of marginal areas, brought about by human activities. |
| Dune | Hill or ridge of wind-deposited sand. |
| Ephemeral stream | A stream that is usually dry because it carries water only in response to specific episodes of rainfall. |
| Inselberg | An isolated mountain remnant characteristic of the late stage of erosion in a mountainous arid region. |
| Interior drainage | A discontinuous pattern of intermittent streams that do not flow to the ocean. |
| Loess | Deposits of windblown silt, lacking visible layers, generally buff-colored, and capable of maintaining a nearly vertical cliff. |
| Longitundinal dunes | Long ridges of sand oriented parallel to the prevailing wind; these dunes form where sand supplies are limited. |
| Parabolic dune | A sand dune similar in shape to a barchan dune except that its tips point into the wind. These dunes often form along coasts that have strong onshore winds, abundant sand, and vegetation that partly covers the sand. |
| Playa | The flat central area o an undrained desert basin. |
| Playa lake | A temporary lake in a playa. |
| Slip= face | The steep, leeward surface of a sand dune that maintains a slope of about 34 degrees. |
| Star dune | An isolated hill of sand that exhibits a complex form and develops where wind directions are variable. |
| Steppe | One of the two types of dry climate. A marginal and more humid variant of the desert that separates it from bordering humid climates. |
| Traverse dunes | A series of long ridges oriented at right angles to the prevailing wind; these dunes form where vegetation is sparse and sand is very plentiful. |
| Ventifact | A cobble or pebble polished and shaped by the sandblasting effect of wind. |
| Yardang | A streamlined, wind-sculpted ridge having the appearance of an inverted ship's hull that is oriented parallel to the prevailing wind. |
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