complement

[ noun kom-pluh-muhnt; verb kom-pluh-ment ]

noun

1. something that completes or makes perfect:

   A good wine is a complement to a good meal.

2. the quantity or amount that completes anything:

   We now have a full complement of packers.

3. either of two parts or things needed to complete the whole; counterpart.
4. full quantity or amount; complete allowance.
5. the full number of officers and crew required on a ship.
6. Grammar.
   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.
7. Geometry. the quantity by which an angle or an arc falls short of 90° or a quarter of a circle. Compare supplement ( def 4 ).
8. Also called absolute complement. Mathematics. the set of all the elements of a universal set not included in a given set.
9. Music. the interval that completes an octave when added to a given interval.
10. Immunology.
    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.
11. complementary color.

verb (used with object)

1. to complete; form a complement to:

   This belt complements the dress better than that one.

2. Obsolete. to compliment.

verb (used without object)

1. Obsolete. to compliment.

complement

noun

1. a person or thing that completes something
2. one of two parts that make up a whole or complete each other
3. a complete amount, number, etc (often in the phrase full complement )
4. the officers and crew needed to man a ship
5. grammar
   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
6. maths the angle that when added to a specified angle produces a right angle
7. 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
8. music the inverted form of an interval that, when added to the interval, completes the octave

   the sixth is the complement of the third

9. immunol a group of proteins in the blood serum that, when activated by antibodies, causes destruction of alien cells, such as bacteria

verb

1. tr to add to, make complete, or form a complement to

complement

/ kŏm′plə-mənt /

1. 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.
2. A complementary color.

Usage

See compliment

Confusables 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.

Other Words From

• com·ple·ment·er noun

Word History and Origins

Origin of complement¹

First recorded in 1350–1400; Middle English, from Latin complēmentum “something that completes,” equivalent to complē(re) “to fill, fill up” + -mentum noun suffix; complete, -ment

Word History and Origins

Origin of complement¹

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

Synonym Study

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.

Example Sentences

“He just had me sing some melodies, or create sounds with my voice that might match or complement or counterpoint the words and phrases,” Gershon said.

From Los Angeles Times

In this respect, “Arcane” in its second season is the perfect show to complement the actual universe’s biggest ongoing battle against fascism, the 2024 presidential election.

From Salon

There are plenty of slick A.I. features to excite Apple fans, and to complement the brand’s new custom-chip-powered hardware: “Writing Tools” for proofreading and editing messages, overhauls of Siri and the Mail app, the added ability to record and transcribe phone calls, and upgrades to the search and edit functions for your photo albums.

From Slate

Ani is the only girl at Headquarters who speaks Russian, and her rusty language skills picked up from her grandmother perfectly complement Ivan’s sexual naivete and boyish charm.

From Salon

Engineers designed the channels to complement flood-control dams and transport water quickly from city streets to the ocean.

From Los Angeles Times

Related Words

• achieve
• integrate