v. de·fined, de·fin·ing, de·fines
a. To state the precise meaning of (a word or sense of a word, for example).
b. To describe the nature or basic qualities of; explain: define the properties of a new drug; a study that defines people according to their median incomes.
a. To make clear the outline or form of; delineate: gentle hills that were defined against the sky.
b. To specify distinctly: define the weapons to be used in limited warfare.
3. To give form or meaning to: "For him, a life is defined by action" (Jay Parini).
To make or write a definition.
[Middle English definen, diffinen, from Old French definir, diffiner, from Latin dēfīnīre, to limit, determine : dē-, intensive pref.; see DE- + fīnis, boundary, limit.]
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.