a. Of or relating to a function.
b. Of, relating to, or indicating a mathematical function or functions.
2. Designed for or adapted to a particular function or use: functional architecture.
a. Capable of performing a function; operative: a functional set of brakes.
b. Able to function personally or socially despite limitations or impairment: a functional alcoholic.
4. Medicine Involving physiological function rather than anatomical structure.
A linear function on vectors whose values are scalars.
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.