adj

• (grammar) Applied to one of the cases of the noun in some languages, the fundamental meaning of the case being removal, separation, or taking away, and to a lesser degree, instrument, place, accordance, specifications, price, or measurement.
• (archaic) Pertaining to taking away or removing.
  "Where the heart is forestalled with misopinion, ablative directions are found needful to unteach error, ere we can learn truth."
• (engineering, nautical, astronautics) Sacrificial, wearing away or being destroyed in order to protect the underlying material, as in ablative paints used for antifouling, or ablative heat shields used to protect spacecraft during reentry. .
  "The inner layer of warship protection consists of ablative armor plate designed to "boil away" when heated. The vaporized armor material scatters a DEW beam, rendering it ineffectual."
• (medicine) Relating to the removal of a body part, tumor, or organ.

noun

• (grammar) The ablative case.