Ablation
(Ab*la"tion) n. [L. ablatio, fr. ablatus p. p. of auferre to carry away; ab + latus, p. p. of ferre carry: cf. F. ablation. See Tolerate.]

1. A carrying or taking away; removal. Jer. Taylor.

2. (Med.) Extirpation. Dunglison.

3. (Geol.) Wearing away; superficial waste. Tyndall.

NASA has added a new use for this word. When spacecraft
re-enter earth's atmosphere they are travelling at such a
high speed that the friction of even rarified air produces
tremendous heat, that could melt any metal. So a special
ceramic tile had to be devised. These are able to withstand
the heat until air resistance has decelerated the spacecraft
to a safe landing speed.It was undetected failure of these
special tiles that cause destruction of Columbia.
As these tiles become incandescent, a small amount of
surface material is lost - this is called "ablation".

James Michener, in Space, has a short foray into the difference between AB-lative (absolutely!) and a-BLATE-ive, with just the meaning you give. The aBLATive heat shield is supposed insulate as it gets hot and wears away slowly, gradually, grudgingly, as the reentering spacecraft is slowed by friction with the atmosphere.

The insulation of the tiles is so important I blush to have omitted mention of it. They could have made the metal twice as thick and still have had cabin get lethally hot.