having a complement or complements.
Mathematics. (of a lattice containing a smallest element and a greatest element) having the property that corresponding to each element of the lattice is a second element such that the greatest lower bound of the two elements is the smallest element of the lattice and the least upper bound of the two elements is the greatest element of the lattice.

Nearby words

  1. complementary hypertrophy,
  2. complementary medicine,
  3. complementary strand,
  4. complementary wavelength,
  5. complementation,
  6. complementizer,
  7. complete,
  8. complete antibody,
  9. complete antigen,
  10. complete blood count

Origin of complemented

Related formsun·com·ple·ment·ed, adjective


[noun kom-pluh-muh nt; verb kom-pluh-ment]


something that completes or makes perfect: A good wine is a complement to a good meal.
the quantity or amount that completes anything: We now have a full complement of packers.
either of two parts or things needed to complete the whole; counterpart.
full quantity or amount; complete allowance.
the full number of officers and crew required on a ship.
  1. a word or group of words that completes a grammatical construction in the predicate and that describes or is identified with the subject or object, as small in The house is small or president in They elected her president.Compare object complement, subject complement.
  2. any word or group of words used to complete a grammatical construction, especially in the predicate, including adverbials, as on the table in He put it on the table, infinitives, as to go in They are ready to go, and sometimes objects, as ball in He caught the ball.
Geometry. the quantity by which an angle or an arc falls short of 90° or a quarter of a circle.Compare supplement(def 4).
Also called absolute complement. Mathematics. the set of all the elements of a universal set not included in a given set.
Music. the interval that completes an octave when added to a given interval.
  1. a system in vertebrate blood of 12 or more proteins that react in a cascade to a cell displaying immune complexes or foreign surfaces, acting in various combinations to coat the cell and promote phagocytosis, make holes in the cell wall, or enhance the inflammatory response.
  2. any of the proteins in the complement system, designated C1, C2, etc.

verb (used with object)

to complete; form a complement to: This belt complements the dress better than that one.
Obsolete. to compliment.

verb (used without object)

Obsolete. to compliment.

Origin of complement

1350–1400; Middle English < Latin complēmentum something that completes, equivalent to complē(re) to fill up (see complete) + -mentum -ment

Related formscom·ple·ment·er, noun

Can be confusedcomplement supplement (see synonym study at the current entry)complement compliment (see usage note at the current entry)

Synonym study

12. Complement, supplement both mean to make additions to something. To complement is to provide something felt to be lacking or needed; it is often applied to putting together two things, each of which supplies what is lacking in the other, to make a complete whole: Two statements from different points of view may complement each other. To supplement is merely to add to: Some additional remarks may supplement his address.

Usage note

Complement and compliment, which are pronounced alike and originally shared some meanings, have become separate words with entirely different meanings. As a noun, complement means “something that completes or makes perfect”: The rare old brandy was a perfect complement to the delicious meal. As a verb, complement means “to complete”: A bright scarf complements a dark suit. The noun compliment means “an expression of praise, commendation, or admiration”: The members paid her the compliment of a standing ovation. The verb compliment means “to pay a compliment to”: Everyone complimented him after the recital. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for complemented

British Dictionary definitions for complemented


noun (ˈkɒmplɪmənt)

a person or thing that completes something
one of two parts that make up a whole or complete each other
a complete amount, number, etc (often in the phrase full complement)
the officers and crew needed to man a ship
  1. a noun phrase that follows a copula or similar verb, as for example an idiot in the sentence He is an idiot
  2. a clause that serves as the subject or direct object of a verb or the direct object of a preposition, as for example that he would be early in the sentence I hoped that he would be early
maths the angle that when added to a specified angle produces a right angle
logic maths the class of all things, or of all members of a given universe of discourse, that are not members of a given set
music the inverted form of an interval that, when added to the interval, completes the octavethe sixth is the complement of the third
immunol a group of proteins in the blood serum that, when activated by antibodies, causes destruction of alien cells, such as bacteria

verb (ˈkɒmplɪˌmɛnt)

(tr) to add to, make complete, or form a complement to

Word Origin for complement

C14: from Latin complēmentum, from complēre to fill up, from com- (intensive) + plēre to fill


Avoid confusion with compliment

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for complemented
Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for complemented




A group of proteins found in normal blood serum and plasma that are activated sequentially in a cascadelike mechanism that allows them to combine with antibodies and destroy pathogenic bacteria and other foreign cells.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for complemented



A group of proteins in blood serum that interact systematically as part of the body's immune response to destroy disease-causing antigens, especially bacteria. Complement proteins interact with antibodies and other chemical substances to cause the disintegration of foreign cells and enhance other immune functions such as phagocytosis.
A complementary color.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.