1. Something added to complete a thing, make up for a deficiency, or extend or strengthen the whole.
2. A section added to a book or document to give further information or to correct errors.
3. A separate section devoted to a special subject inserted into a periodical, such as a newspaper.
4. See dietary supplement.
5. See supplementary angle.
tr.v. (-mĕnt′) sup·ple·ment·ed, sup·ple·ment·ing, sup·ple·ments
To provide or form a supplement to.
[Middle English, from Old French, from Latin supplēmentum, from supplēre, to complete; see SUPPLY.]
sup′ple·men·tari·ty (-târĭ-tē) n.
sup′ple·menta·ry (-mĕntə-rē, -trē), sup′ple·mental (-mĕntl) adj.
sup′ple·men·tation (-mĕn-tāshən) n.
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.