Caustic

Definitions

1. Any substance or means which, applied to animal or other organic tissue, burns, corrodes, or destroys it by chemical action; an escharotic.
   countable, uncountable
2. The envelope of reflected or refracted rays of light for a given surface or object.
   countable, uncountable
3. The envelope of reflected or refracted rays for a given curve.
   countable, uncountable
4. Caustic soda.
   informal, uncountable

Equivalents

Examples

“The association of the heavenly bodies with known metals and also with human organs and destinies goes back to ancient Chaldea, the land⟳ of astrologers. In Chaucer’s words: ‘The seven bodies eek, lo hear⟳ anon. Sol gold is, and Luna silver we declare⟳; Mars yron, Mercurie is quyksilver; Saturnian leed; and Jubitur is tyn, and Venus coper, by my fathers kyn.’ […] Corresponding names were bestowed upon salts of these metals by the alchemists, and some of them have⟳ persisted down to the present⟳ day. Some examples are lunar caustic (silver nitrate); vitriol of Venus (copper sulphate); sugar of Saturn (lead⟳ acetate); and vitriol of Mars, or Martial vitriol (ferrous sulphate).”

CEFR level