di·rec·tion·al (dĭ-rĕkshə-nəl, dī-)
1. Of or indicating direction: an automobile's directional lights.
2. Electronics Capable of receiving or sending signals in one direction only.
3. Relating to guidance in effort, behavior, or thought: directional training.
A directional signal.
di·rec′tion·ali·ty (-shə-nălĭ-tē) n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. 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.