Measure of the bending or refraction of a beam of light on entering a denser medium (the ratio between the sine of the angle of incidence of the ray of light and the sine of the angle of refraction). It is constant for pure substances under standard conditions. Used as a measure of sugar or total solids in solution, purity of oils, etc.

A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved.