n. Abbr. grad.
1. A rate of inclination; a slope.
2. An ascending or descending part; an incline.
3. Physics The rate at which a physical quantity, such as temperature or pressure, changes in response to changes in a given variable, especially distance.
4. Mathematics A vector having coordinate components that are the partial derivatives of a function with respect to its variables.
5. Biology A series of progressively increasing or decreasing differences in the growth rate, metabolism, or physiological activity of a cell, organ, or organism.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.