n.
- Something that completes, makes up a whole, or brings to perfection.
- The quantity or number needed to make up a whole: shelves with a full complement of books.
- Either of two parts that complete the whole or mutually complete each other.
- An angle related to another so that the sum of their measures is 90°.
- Grammar. A word or words used to complete a predicate construction, especially the object or indirect object of a verb; for example, the phrase to eat ice cream in We like to eat ice cream.
- Music. An interval that completes an octave when added to a given interval.
- The full crew of officers and enlisted personnel required to run a ship.
- Immunology. A complex system of proteins found in normal blood plasma that combines with antibodies to destroy pathogenic bacteria and other foreign cells. Also called alexin.
- Mathematics & Logic. For a universal set, the set of all elements in the set that are not in a specified subset.
- A complementary color.
To serve as a complement to: Roses in a silver bowl complement the handsome cherry table.
[Middle English, from Old French, from Latin complēmentum, from complēre, to fill out. See complete.]
USAGE NOTE Complement and compliment, though quite distinct in meaning, are sometimes confused because they are pronounced the same. As a noun, complement means "something that completes or brings to perfection" (The antique silver was a complement to the beautifully set table); used as a verb it means "to serve as a complement to." The noun compliment means "an expression or act of courtesy or praise" (They gave us a compliment on our beautifully set table), while the verb means "to pay a compliment to."
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
