ab·la·tion 
(ă-blāshən)
(ă-blāshən)n.
1. Surgical excision or amputation of a body part or tissue.
2. The erosive processes by which a glacier is reduced.
3. Aerospace
a. 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.
b. The reduction or removal of heat-protective surface material by aerodynamic friction, as from a heat shield.
[Late Latin ablātiō, ablātiōn-, from Latin ablātus, past participle of auferre, to carry away : ab-, away; see AB-1 + lātus, carried; see telə- in the Appendix of Indo-European roots.]
ab·lator n.