complement

n.

1. 1. Something that completes, makes up a whole, or brings to perfection.
   2. The quantity or number needed to make up a whole: shelves with a full complement of books.
   3. Either of two parts that complete the whole or mutually complete each other.
2. An angle related to another so that the sum of their measures is 90°.
3. 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.
4. Music. An interval that completes an octave when added to a given interval.
5. The full crew of officers and enlisted personnel required to run a ship.
6. 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.
7. Mathematics & Logic. For a universal set, the set of all elements in the set that are not in a specified subset.
8. A complementary color.

tr.v., -ment·ed, -ment·ing, -ments. (-mĕnt')
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."

For more information on complement, visit Britannica.com.

A group of proteins in the blood and body fluids that play an important role in humoral immunity and the generation of inflammation. When activated by antigen-antibody complexes, or by other agents such as proteolytic enzymes (for example, plasmin), complement kills bacteria and other microorganisms. In addition, complement activation results in the release of peptides that enhance vascular permeability, release histamine, and attract white blood cells (chemotaxis). The binding of complement to target cells also enhances their phagocytosis by white blood cells. The most important step in complement system function is the activation of the third component of complement (C3), which is the most abundant of these proteins in the blood.

Genetic deficiencies of certain complement subcomponents have been found in humans, rabbits, guinea pigs, and mice. Certain deficiencies lead to immune-complex diseases, such as systemic lupus erythematosus; other deficiencies result in increased susceptibility to bacterial infections, particularly those of the genus Neisseria (for example, gonorrhea and meningococcal meningitis), and hereditary angioneurotic edema. See also Complement-fixation test; Immunity.

---

The number derived by subtracting a number from a base number. For example, the tens complement of 8 is 2. In set theory, complement refers to all the objects in one set that are not in another set.

Complements are used in digital circuits, because it's faster to subtract by adding complements than by performing true subtraction. The binary complement of a number is created by reversing all bits and adding 1. The carry from the high-order position is eliminated. The following example subtracts 5 from 8.

     Decimal    Binary    Complement
      8          1000      1000
     -5         -0101     +1011
     __         _____     _____
      3          0011      0011

Download Computer Desktop Encyclopedia to your iPhone/iTouch

noun

1. Something that completes another: supplement. See agree/disagree, part/whole.
2. Something added to another for embellishment or completion: accompaniment, enhancement, enrichment. See accompanied.

verb

To supply what is lacking: complete, fill in (or out), round (off or out), supplement. See agree/disagree, part/whole.

v

Definition: complete
Antonyms: take away

---

n

One of 11 complex, enzymatic serum proteins. In an antigen-antibody reaction, complement causes lysis. Complement is also involved in anaphylaxis and phagocytosis.

The difference between an octave and a given simple interval, hence the INVERSION of that interval at the octave; the complement of a perfect 5th is a perfect 4th.

---

The complement of a set S is the class of objects that are not members of S. In standard set theory the complement of a set cannot itself be a set: only those things not in the set but meeting some further restriction can form a set. See separation, axiom of.

The collective term for proteins of the complement system, known separately as Cl, C2, C3, etc. The serum complement tends to be deficient in some endurance athletes. This may contribute to their increased susceptibility to infection.

A complex series of enzymatic proteins occurring in normal serum that are triggered in a cascade manner by, and combine with, the antibody–antigen complexes, producing lysis when the antigen is an intact cell. Complement comprises 25 to 30 discrete proteins, labeled numerically as C1 to C9, and by letters, i.e. B, D, P, etc., and with C1 being divided into subcomponents C1q, C1r and C1s. Components C3 and C5 are involved in the generation of anaphylatoxin and in the promotion of leukocyte chemotaxis, the result of these two activities being the inflammatory response. C1 and C4 are involved in the neutralization of viruses. The components also combine in various sequences to participate in other biological activities, including antibody-mediated immune lysis, phagocytosis, opsonization and anaphylaxis. The complement system is known to be activated by the immunoglobulins IgM and IgG.

• alternate c. pathway, alternative c. pathway — the sequence in which complement components C3 and C5 to C9 are activated without participation by C1, C2 and C4 or the presence of an antibody–antigen complex.
• c. cascade — the sequence of reactions, each being the catalyst for the next, that leads to the terminal complement pathway and cell lysis. There are two pathways for activation of C3, the ‘classical’ (below) and the ‘alternate’ (above).
• classical c. pathway — the one in which all of the complement components C1 to C9 participate and is triggered by antibody–antigen complexes.
• c. deficiency — various complement components may be deficient without serious effects on the host. C3 deficiency is most severe and occurs in humans, Brittany spaniels and Finnish-Landrace lambs. Increased susceptibility to infections results.
• c. fixation tests — utilize antibody–antigen reaction and result in hemolysis to determine the presence of various organisms in the blood. Involves two stages. In the first, also referred to as the test system, antigen is mixed usually with serial dilutions of a test serum in the presence of complement. If the serum contains antibody, i.e. is positive, an antibody–antigen complex is formed which also binds (fixes) complement. In the second stage, also called the indicator system, sheep red blood cells coated with specific, usually rabbit anti-sheep red blood cell antibody are added. The red blood cells are said to be sensitized. If antibody was not present in stage 1, then the free complement lyses the sensitized sheep red blood cells. The basis of many serological tests including those for glanders, tuberculosis and contagious bovine pleuropneumonia. Called also Bordet–Gengou phenomenon. See also immunity.
• c. regulatory proteins — a set of at least seven proteins that are present in plasma (C1 INH, C4b-binding protein, factor H and factor I) or present in cell membranes (decay-accelerating factor [DAF], membrane cofactor protein [MCP] and homologous restriction factor [HHF]) that modulate the complement proteins and protect ‘innocent’ bystander cells and tissues from complement damage.
• terminal c. pathway — the final stages of complement activation in which C5, C6, C7, C8 and C9 are activated; common to both the alternate and classical pathways.

IN BRIEF: To make whole.

Courage is the complement of fear. A man who is fearless cannot be courageous. (He is also a fool.) — Robert Heinlein (1907-1988).

Tutor's tip: I had to "compliment" (express approval or praise) the chef on what an excellent "complement" (something that goes well with something else) the potatoes made to the roast beef.

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - besætning, omsagnsled, komplement
v. tr. - komplementere, fuldende

Nederlands (Dutch)
complement, volle bezetting, aanvullen, sluitstuk

Français (French)
n. - (gén, Math, Ling) complément, effectif, personnel
v. tr. - compléter, se compléter

Deutsch (German)
n. - Ergänzung, Vervollkommnung, Vervollständigung
v. - ergänzen, vervollständigen

Ελληνική (Greek)
n. - συμπλήρωμα, παραπλήρωμα, πλήρωμα (σκάφους κ.λπ.), (γραμμ.) κατηγορούμενο ή δεύτερο αντικείμενο, συμπλήρωμα ρήματος

Italiano (Italian)
conclusione, complemento, guarnigione

Português (Portuguese)
n. - complemento (m), totalidade (f), aperfeiçoamento (m), tripulação (f) de navio

Русский (Russian)
дополнение, полный состав

Español (Spanish)
n. - complemento, efectivo
v. tr. - complementar

Svenska (Swedish)
n. - komplement, fullt antal, bestämning (gram.)

中文（简体）(Chinese (Simplified))
补足物, 余角, 补语, 补助, 补足

中文（繁體）(Chinese (Traditional))
n. - 補足物, 餘角, 補語
v. tr. - 補助, 補足

한국어 (Korean)
n. - 보충물, 보어
v. tr. - 보충하다

日本語 (Japanese)
n. - 補足するもの, 補語, 全数, 乗組定員, 補足物
v. - 補って完全にする

العربيه (Arabic)
‏(الاسم) تكمله, تتمه, العدد المقرر لتتمه عمل ما‏

עברית (Hebrew)
n. - ‮השלמה, משלים, תקן מלא‬
v. tr. - ‮השלים‬

If you are unable to view some languages clearly, click here.

To select your translation preferences click here.