1. Constituting or being part of the nature or essence of something; inherent: "In that era of general good will ... few Americans doubted the essential goodness of their society" (David Halberstam).
2. Fundamentally important or necessary: essential ingredients. See Synonyms at indispensable.
3. Medicine Of, relating to, or being a condition or a disease whose cause is unknown: essential hypertension.
4. Biochemistry Being a substance that is required for normal functioning but cannot be synthesized by the body and therefore must be included in the diet: essential amino acids.
1. Something fundamental.
2. Something necessary or indispensable.
es·sen′ti·ali·ty (-shē-ălĭ-tē), es·sential·ness n.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 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.