ablation

Surgical excision or amputation of a body part or tissue.

The erosive processes by which a glacier is reduced.

Aerospace

1. The dissipation of heat generated by atmospheric friction, especially in the atmospheric reentry of a spacecraft or missile, by means of a melting heat shield.

2. The reduction or removal of heat-protective surface material by aerodynamic friction, as from a heat shield.

The wearing away or destruction of the outer or forward surface of an object, such as a meteorite or a spacecraft, as it moves very rapidly through the atmosphere. The friction of the air striking the object heats and often melts or burns its outer layers. Spacecraft and missiles are often equipped with heat shields designed to wear away by ablation in order to prevent heat from building up in structurally important parts.

The process by which snow and ice are removed from a glacier or other mass of ice. Ablation typically occurs through melting, sublimation, wind erosion, or calving. ◇ The ablation zone is the area of a glacier that has the lowest elevation, where annual water loss is greater than the annual accumulation of snow.