in physics, an appellation given to medicines of so hot and fiery a nature, that, being applied, consume, and as it were burn, the texture of the parts, like hot iron.

Caustics are generally divided into four sorts; the common stronger caustic, the common milder caustic, the antimonial caustic, and the lunar caustic. See PHARMACY and CHEMISTRY.

Caustic Curve, in the higher geometry, a curve formed by the concurrence or coincidence of the rays of light reflected from some other curve.