Definition of complement in English:



  • 1A thing that completes or brings to perfection.

    ‘the libretto proved a perfect complement to the music’
    • ‘VoB will be a complement to your existing phone, not its complete replacement.’
    • ‘As well as these tinsel tales, there are large numbers of records, still being slowly translated, which provide a complement to the operatic version of Persian history.’
    • ‘As a complement to the board's oversight, FDA will improve transparency by sharing drug safety information sooner and more broadly and conveniently.’
    • ‘The private economy has long been considered a complement to the State sector.’
    • ‘Many retailers are also becoming more active in the seed business or are partnering with seed companies, so seed treatment as a whole is a great complement to and natural extension of the seed business.’
    • ‘Blogging is a complement to traditional media, not a replacement for it, and if the traditional media gets hurt, the quality of blogging will also suffer.’
    • ‘For these reasons, we need, as a crucial complement to the commercial media, a broad range of independent, nonprofit and noncommercial outlets.’
    • ‘A good example is the chapter by Steven King, who notes that poor relief payments were not so much an alternative to work as a complement to it, supplementing low earnings.’
    • ‘Tending bar at Chicago's Sidetrack to make extra money, Hall saw the job as the perfect complement to his theater career.’
    • ‘But what I hope that more faculties are beginning to discover is that blogging can serve as an important complement to the traditional forums for scholarship.’
    • ‘I'm trying to find people who use the internet for their spiritual development either as a replacement for an established place of worship or as a complement to organised religion.’
    • ‘The butter made at the summer dairies was easily stored in wooden boxes and small barrels and during the winter was an important complement to most foods.’
    • ‘And I'm going to start off a new occasional feature, a complement to my ‘How Not to Do It’ series of lab stories.’
    • ‘Today, world-class designers no longer consider footwear simply a complement to the dress but an article of apparel designed within the context of a single message.’
    • ‘During the eighteenth century fashionable accessories became an important complement to a lady's attire.’
    • ‘These are both very strong extras that make a good complement to the OAV.’
    • ‘Tyrosine is a good choice as a stand-alone supplement or as a complement to other fat-burning ingredients.’
    • ‘Trade liberalization, the complement to deregulated capital markets, also plays a significant role in raising inequality and limiting efforts at poverty reduction.’
    • ‘Australian collectors are still somewhat of a rarity in this field, even though European Impressionist pictures are without doubt a good complement to any Australian art collection.’
    • ‘The accompanying mushrooms and salad were the perfect complement to the huge slab of meat.’
    accompaniment, companion, addition, supplement, accessory, adjunct, trimming, finishing touch, final touch
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  • 2[in singular] A number or quantity of something required to make a group complete.

    ‘at the moment we have a full complement of staff’
    • ‘A full complement of Vancouver police officers was on hand for traffic control and to ensure the safety of people participating in the peaceful demonstration.’
    • ‘Accommodation along Shell Beach is limited to a single camp run by an Arawak family (with a full complement of pet dogs, parrots, and tortoises).’
    • ‘In a sign of the gravity of the talks, Dr Reid was accompanied by a full complement of civil servants.’
    • ‘This will require a full complement of diplomatic, political and military efforts.’
    • ‘Tetraploids, inheriting a full complement of chromosomes from each parent, and thus having double the normal allowance, occur in nature or can be induced.’
    • ‘The net effect of fooling ourselves in these basic ways has been to project a full complement of thoughts and emotions that are utterly incompatible with the species in question.’
    • ‘If there's a full complement of 10 guests, that works out at just 15 litres each - which means a quick stop-start shower rather than a long soak.’
    • ‘He would say that but the company now has a full complement of drivers, which suggests there is substance to his claim.’
    • ‘The instruments included three rhythm sections, bongo drums, piano, a full complement of brass, saxophones, flutes, clarinets, guitars and even two bassoons.’
    • ‘He gave an assurance that public neonatal units across the country would receive a full complement of drugs by tomorrow, even if his ministry had to source them from the region.’
    • ‘On June 15, we were able to announce a full complement of senior staff, with a truly exceptional mix of experience and diversity.’
    • ‘It does not just provide office space for a company to work in, it offers a full complement of strategic services that aim to transform a great business idea into a global player.’
    • ‘The cell is then stretched and split into two halves on the framework of microtubules, each half containing a full complement of chromosomes.’
    • ‘‘An adequate service for children at risk cannot be provided without a full complement of social workers,’ he said.’
    • ‘They have a full complement of IT staff, and hardware to cater to a worldwide user base that requires their services 24 hours a day, seven days a week.’
    • ‘We have a full complement of both vehicles and soldiers who can carry out any tasks that they are required to do.’
    • ‘St Cecilia's, building its way to a full complement of 900 pupils, currently has just 11, 12 and 13-year-olds on roll.’
    • ‘A single pollinator imports sufficient pollen into an individual fig to initiate a full complement of seeds.’
    • ‘The minimum wage would be 89 shillings 11 pence per week for those producing a full complement of weaves and 74 shillings for those who didn't.’
    • ‘The Learjet has a maximum range of just over 2,000 nautical miles with a full complement of passengers which means it can reach all corners of the newly enlarged EU from 2004.’
    amount, total, aggregate, contingent, company
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    1. 2.1The number of people required to crew a ship.
      ‘almost half the ship's complement of 322 were wounded’
      • ‘For two years, the Sutherland has been classed as a mixed ship, although its complement of females was only ever four officers out of a crew of 170.’
      • ‘Each ship will have a complement of typically 1,200, including 600 air crew.’
      • ‘The improved accommodation aboard for the ship's complement of 51 has gone down well with crew.’
      • ‘A complement of marines will board the vessel once you succeed in capturing it.’
      • ‘Of the ship's complement of 600 officers and men, well over 25% were either killed or wounded.’
      • ‘Many of the ship's complement were adventurers from noble families, and jewellery and coins, mainly gold, percolated to the bottom of the shingle-filled gullies.’
      • ‘The normal complement of flight-deck troubleshooters and deck crew was in sight and out of harm's way, so my gaze shifted inward.’
      • ‘The trials have also shown that the new process does not add to the burden on the ship's technical complement.’
      • ‘However, she refers to the muster for a boat called Queen, 74 guns, with a ship's complement just of 300 men.’
      • ‘He lost all but one of his six ships, and two thirds of the crews he shipped (700 survived out of an original complement of 2000), most of them to scurvy.’
      • ‘She has a complement of six officers and 27 men as permanent crew and can accommodate and impart sail training to 30 cadets.’
      • ‘The ship's complement is 210 crew with 13 officers.’
      • ‘I am led to believe that the Qantas crew involved in this week's emergency disembarkation in Japan didn't have a Japanese language speaker as part of the crew complement.’
      • ‘Eliminating meals will also mean the normal complement of cabin crew can be cut from six to three.’
      • ‘The crew complement was further reduced by the need to leave two particularly severe cases behind in hospital.’
      • ‘His fleet usually consisted of more than 200 ships of different sizes and it had a total complement of about 20,000 sailors.’
      • ‘Without the vehicle, the crew complement cannot be increased.’
      • ‘Just 79 of the ship's complement of 284 souls survived.’
      • ‘A sailor is assigned to an aircraft carrier that has a complement of 5000 in its crew.’
      • ‘It had a crew of three and could carry an infantry complement of eight.’
    2. 2.2Geometry The amount in degrees by which a given angle is less than 90°
    3. 2.3Mathematics The members of a set that are not members of a given subset.
      • ‘Likewise, in base 2, the complement of a number is obtained by subtraction from a row of 1's.’
  • 3Grammar
    One or more words, phrases, or clauses governed by a verb (or by a nominalization or a predicative adjective) that complete the meaning of the predicate.

    • ‘So it should be perfectly fine to conjoin two noun phrases as complements of expect, and indeed it is.’
    • ‘Complement clauses are subordinate clauses that function as complements of a word: that they were too noisy in She told them that they were too noisy.’
    • ‘For many people, ‘feel like’ has become a complex verb that takes sentential complements.’
    • ‘Looks like it managed it, too - provided we take ‘like’ to be a preposition, not an adjective taking a noun phrase complement.’
    • ‘Recall that a verb governs an object, and the head of a phrase governs the complement.’
    1. 3.1(in systemic grammar) an adjective or noun that has the same reference as either the subject (as mad in he is mad) or the object (as mad in he drove her mad)
  • 4Physiology
    A group of proteins present in blood plasma and tissue fluid that combine with an antigen–antibody complex to bring about the lysis of foreign cells.

    • ‘If the HLA antigen and specific antibody bind, and complement is added, the cells in that well will be killed.’
    • ‘CD21 is a molecule on the surface of B cells that attaches to an immune system protein called complement.’
    • ‘The DAT is usually positive, confirming the presence of IgG antibodies with or without complement on the red cells.’
    • ‘An example is a transfusion reaction in which IgG and IgM anti-red-cell antibodies activate complement and cause cell lysis.’
    • ‘Red blood cell susceptibility to complement was ruled out via a negative sucrose hemolysis test thus precluding a diagnosis of PNH.16’


  • 1 Add to (something) in a way that enhances or improves it; make perfect.

    ‘a classic blazer complements a look that's stylish or casual’
    • ‘The team's vast improvement can be traced to a more balanced offense, which complements an improving defense.’
    • ‘Here, its earthy quality complements a traditional design.’
    • ‘Select a quality cookbook that complements your tastes and reflects your culinary goals and skills.’
    • ‘This capability complements policy-based management features that allow automated or advised actions, based on conditions detected through advanced diagnostics.’
    • ‘The funky banded-bottom top elongates her torso, while the shapely cord blazer complements her curves.’
    • ‘To take the garden further, water features were developed to complement the natural drainage through the property.’
    • ‘We will be looking to bring in some relatively younger players to complement Paul and Rich in there.’
    • ‘This aural quality thus complements the film in its evocation of the 1920's era of Woolf's Richmond as well as the modern milieu of contemporary New York.’
    • ‘It was complemented by two classic marble statues of Greek gods situated at each side of the entrance.’
    • ‘Interactive television enables us to add a whole host of features to complement our existing television coverage.’
    • ‘Riding last year's breakthrough, he's using slightly improved on-base skills to complement his power-speed combination.’
    • ‘This extra fund will complement your official scheme when retirement income is totaled.’
    • ‘There was something about his personality that lent itself to New York, a stubborn quality that complements a stubborn city.’
    • ‘But at least they deliver what they charge the people for: a broadcast that is full of quality and that complements the sport.’
    • ‘Its old fashioned appearance is complemented by modern design extras.’
    • ‘Played just once after being triggered, each track generally contains an upbeat quality that complements the action well.’
    • ‘Our flagship focus is complemented by other efforts to improve soldier and family quality of life.’
    • ‘The selection of make-up should complement skin tone, features and attire.’
    • ‘The extras complement the film without being overkill, and it's a pleasant addition to any fan's library.’
    • ‘Picture books shared with your children provide daily opportunities to contribute to and complement their developing concepts about picture reading and print.’
    accompany, go with, round off, set off, suit, harmonize with, be the perfect companion to, be the perfect addition to, add the finishing touch to, add the final touch to, add to, supplement, augment, enhance, complete
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    1. 1.1Add to or make complete.
      ‘the proposals complement the incentives already available’
      • ‘They were like twins, one half perfectly complementing the other.’
      • ‘Or they may think that there are different sets that in some sense correspond to or complement one another.’
      • ‘The support will complement the $81 million already available through U.N. and other sources.’
      • ‘The proposed initiative complements The Army Distance Learning Program by extending training from the classroom to the entity level.’
      • ‘Or, better yet, you can offer the consumer an item to complement something he or she already has - for example, mustard for hot dogs.’
      • ‘He now has speed over the ground to complement his already impressive decision making ability.’
      • ‘Fifteen years in the making, this is truly an epic achievement whose own place in the art-historical canon perfectly complements the now unquestionably monumental status of its subject.’
      • ‘The Nubira complements the already strong line up of Matiz, Kalos and Tacuma.’
      • ‘The harmonica in this song is perfectly placed and complements the Neil Young-style guitar so well that it almost makes you sigh.’
      • ‘The first being that institutions should be designed to complement what is existing in the country.’
      • ‘Movement and grace must complement what has been left unsaid by the music.’
      • ‘I am pleased to hear that a good variety of businesses have made the decision to locate here and this will complement the already thriving business community locally.’
      • ‘Five more endowed chairs are proposed to complement the Goldring Chair in Canadian Studies.’
      • ‘Bosses at Pizza Pioneer, which in July will celebrate its 16th anniversary, have decided to open during the day to complement its already buoyant evening business.’
      • ‘This could be complemented by careful design of payment mechanisms aligning the financial incentives faced by physicians.’
      • ‘A home exercise programme can usefully complement the organised sessions.’
      • ‘The national champion lacked the intensity of concentration to complement her fighting qualities, and thus it was a struggle for her.’
      • ‘He is working on his off-speed pitches to complement his fastball and splitter.’
      • ‘The coordinator will look at ways to create additional events to complement those which already take place in the region.’
      • ‘Ian is an aspiring journalist and promises to provide provocative news programs to complement the already regular news we offer every day at noon.’


Complement and compliment (together with related words such as complementary and complimentary) are frequently confused. They are pronounced in the same way but have quite different meanings: as a verb, complement means ‘add to something in a way that enhances or improves,’ as in a classic blazer complements a look that's smart or casual, while compliment means ‘admire and praise someone for something,’ as in he complimented her on her appearance. Complementary means ‘forming a complement or addition, completing,’ as in I purchased a suit with a complementary tie. This is often confused with complimentary, for which one sense is ‘given freely, as a courtesy’: honeymooners receive complimentary fruit and flowers


Late Middle English (in the sense completion): from Latin complementum, from complere fill up (see complete). Compare with compliment.