ju·ve·nile (jvə-nīl′, -nəl)
a. Not fully grown or developed; young.
b. Of or characteristic of a young animal that has not reached sexual maturity: a bird still in juvenile plumage.
2. Characteristic of, intended for, or appropriate for children or young people: juvenile fashions.
3. Marked by immaturity; childish: juvenile behavior. See Synonyms at young.
4. Geology Relating to or being water, gas, or a mineral-rich fluid believed to have originated from magma and to have come to the earth's surface for the first time.
a. A young person; a child.
b. A young animal that has not reached sexual maturity.
c. A two-year-old racehorse.
2. An actor who plays roles of children or young persons.
3. A children's book.
[Latin iuvenīlis, from iuvenis, young; see yeu- in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.