adj. & n.
--adj.
1. that burns or corrodes organic tissue.
2 sarcastic, biting.
3 Chem. strongly alkaline.
4 Physics formed by the intersection of reflected or refracted parallel rays from a curved surface.
--n.
1. a caustic substance.
2 Physics a caustic surface or curve.
Phrases and idioms:
caustic potash potassium hydroxide. caustic soda sodium hydroxide.
Derivatives:
caustically adv. causticity n.
Etymology: L causticus f. Gk kaustikos f. kaustos burnt f. kaio burn