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noun com·ple·ment \ˈkäm-plə-mənt\

Simple Definition of complement

  • : something that completes something else or makes it better

  • : the usual number or quantity of something that is needed or used

  • grammar : a word or group of words added to a sentence to make it complete

Full Definition of complement

  1. 1 a :  something that fills up, completes, or makes perfect b :  the quantity, number, or assortment required to make a thing complete <the usual complement of eyes and ears — Francis Parkman>; especially :  the whole force or personnel of a ship c :  one of two mutually completing parts :  counterpart

  2. 2 a :  the angle or arc that when added to a given angle or arc equals a right angle in measure b :  the set of all elements that do not belong to a given set and are contained in a particular mathematical set containing the given set c :  a number that when added to another number of the same sign yields zero if the significant digit farthest to the left is discarded —used especially in assembly language programming

  3. 3 :  the musical interval required with a given interval to complete the octave

  4. 4 :  an added word or expression by which a predication is made complete (as president in “they elected him president” and beautiful in “he thought her beautiful”)

  5. 5 :  the thermolabile group of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (as bacteria and foreign blood corpuscles)

Examples of complement

  1. With the loss of just one American and four Japanese carriers, including their complements of aircraft and many of their superbly trained fliers … , Midway … put the Japanese navy at a disadvantage from which it never recovered. —David M. Kennedy, Atlantic, March 1999

  2. Exact observation of the outer world was the complement to a literal reading of Scripture. —Garry Wills, Under God, 1990

  3. The usual complement of Kremlin guards was about, one company of infantry with light arms. —Tom Clancy, Red Storm Rising, 1986

  4. His faults are accepted as the necessary complement to his merits. —W. Somerset Maugham, Moon and Sixpence, 1919

  5. The scarf is a perfect complement to her outfit.

  6. a full complement of farm animals

  7. her usual complement of attendants

  8. a ship's complement of officers

  9. President in they elected her president and to work in he wants to work are different kinds of complements.

Illustration of complement

Origin of complement

Middle English, from Latin complementum, from complēre to fill up, complete, from com- + plēre to fill — more at full

First Known Use: 14th century



verb com·ple·ment \ˈkäm-plə-ˌment\

Simple Definition of complement

  • : to complete something else or make it better

Full Definition of complement


  1. intransitive verb
  2. :  to exchange formal courtesies

  3. transitive verb
  4. 1 :  to complete or enhance by providing something additional :  to be complementary to <the illustrations complement the text>

  5. 2 obsolete :  compliment

Examples of complement

  1. Carrots often work even better than sticks, so I propose a skinny subsidy to complement the fat tax. —Jonathan Rauch, Atlantic, December 2002

  2. The love of Bottom's bottomless vision at least complements, if it does not transcend, the rational love of Theseus. —Frank Kermode, Shakespeare's Language, 2000

  3. … his ice-blue Appalachian eyes glint through horn-rimmed glasses, which complement his salt-and-pepper beard. —Henry Louis Gates, Jr., New Yorker, 19 June 1995

  4. … lively photographs, illustrations and cartoons designed to complement the meanings of the poems and give a leg-up to the imagination. —Carol Ann Duffy, Times Literary Supplement, 4-10 Dec. 1987

  5. The shirt complements the suit nicely.

  6. a delicious dinner complemented by a splendid dessert

  7. The soup and salad complement each other well.

Origin of complement

(see 1complement)

First Known Use: 1602

Medical Dictionary


noun com·ple·ment \ˈkäm-plə-mənt\

Medical Definition of complement

  1. 1:  a group or set (as of chromosomes or DNA) that is typical of the complete organism or one of its parts—see chromosome complement

  2. 2:  a complementary color

  3. 3:  the thermolabile group of proteins in normal blood serum and plasma that in combination with antibodies causes the destruction especially of particulate antigens (as bacteria and foreign blood corpuscles)

Seen and Heard

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February 8, 2016

to clear from accusation or blame

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