Meaning

noun the case indicating the agent in passive sentences or the instrument or manner or place of the action described by the verb

adjective relating to the ablative case

adjective tending to ablate; i.e. to be removed or vaporized at very high temperature

originFrom Middle English ablative, ablatife, ablatyf, ablatif, from Old French ablatif (“the ablative case”), from Latin ablātīvus (“expressing removal”), from ablātus (“taken away”), from auferō (“to take away”). The engineering/nautical sense originates from ablate + -ive.

Etymology from Wiktionary, CC BY-SA 3.0