Meaning

noun any chemical substance that burns or destroys living tissue

adjective harsh or corrosive in tone

adjective of a substance, especially a strong acid; capable of destroying or eating away by chemical action

originFrom the Latin causticus (“burning”), from Ancient Greek καυστικός (kaustikós, “burning”), from καυστός (kaustós, “burnt”) + -ικός (-ikós).

Etymology from Wiktionary, CC BY-SA 3.0