Definition of chemical in English:


(also chem.)


  • 1Relating to chemistry or the interactions of substances as studied in chemistry.

    ‘the chemical composition of the atmosphere’
    • ‘The bilayer is not a homogeneous film, but its chemical composition and molecular structure distinctly varies along the membrane normal.’
    • ‘This resistance to chemical oxidation is likewise due to the resonance stability of the benzene.’
    • ‘Now, let us examine the chemical composition of lipids.’
    • ‘When a galaxy is bright enough that its starlight can be seen directly, we can use spectroscopy to discern its chemical composition and are able to relate it to nearby galaxies around us today.’
    • ‘Explosives are substances that produce violent chemical or nuclear reactions.’
    • ‘That kind of resolution allows exquisitely exact areas to be analyzed for chemical composition.’
    • ‘The differences in the chemical composition of the two give hints about how Chinese brewing may have evolved.’
    • ‘It may also be in part caused by vigorous chemical interaction between the silicate mantle and the iron core.’
    • ‘Typical photopolymers use a single chemical process for bonding molecules together both to form the medium and perform the recording.’
    • ‘These left-over electrons are the ones farthest from the nucleus and because of this they will determine the chemical interactions of the atom with other atoms.’
    • ‘In its simplest terms, a chemical standard is a substance for which the exact composition is known.’
    • ‘Elements are materials that cannot be reduced to simpler substances by normal chemical means.’
    • ‘This new measurement technique will allow scientists to detect the chemical composition of the Martian atmosphere, ionosphere, and surface.’
    • ‘In fairness, any radiation that can ionize an atom can affect chemical changes in a substance.’
    • ‘The third atom can detach from the ozone molecule and reattach to molecules of other substances, changing their chemical composition.’
    • ‘These resonant frequencies depend on the chemical composition of the substance: which atoms it contains and how they are joined together.’
    • ‘Many of them are enzymes, molecules that catalyse processes of chemical change.’
    • ‘The chemical composition of the air is not a precondition for life but the result of it.’
    • ‘Scientists have long used ultra-fine glass tubes known as capillaries to analyze the chemical makeup of substances.’
    • ‘The number of solute particles which form in a solution depends on the chemical nature of the solute.’
    technological, technical
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    1. 1.1Relating to chemicals.
      ‘chemical treatments for killing fungi’
      • ‘Why would a chemical substance as seemingly innocuous as milk sugar cause a body misery?’
      • ‘These days, Grace is working to undo the damage done by the sun's harsh rays, treatments involving microdermabrasion and chemical peels.’
      • ‘They'd proposed a system of shed inspections and post-harvest chemical treatment, to ensure the disease couldn't spread interstate.’
      • ‘Water treatment chemical suppliers are becoming more global, especially European ones who moved into the United States.’
      • ‘Lipids belong to a larger class of chemical substances: esters.’
      • ‘The water treatment chemical industry in the United States is still not concentrated, but it has undergone definite consolidation in the past two decades.’
      • ‘Treatment methods can be chemical or ablative.’
      • ‘Motives for merger, acquisition and divestiture activity in the water treatment chemical industry are varied.’
      • ‘When we consider chemical substances most can exist in any of the three states.’
      • ‘Councillors have been told that fitting water filtering and chemical treatment would cost £223,000 plus annual running costs of £45,220.’
      • ‘The hormone treatment is straightforward chemical castration - I am now impotent but it's an advantageous trade-off against a possibly fatal alternative.’
      • ‘If you have relaxed hair (as explained below in the chemical treatments section), it is best to use a natural bristle brush.’
      • ‘First, DDT, like most chemical substances, is reasonably safe when used responsibly, and harmful when used indiscriminately.’
      • ‘Just as the sweet smells of fall fill the air, the residents of the housing complex where I live are notified again - for the fourth time this year - of a chemical lawn treatment.’
      • ‘This new laser treatment may replace deep chemical peels and laser skin resurfacing, which often leave the skin raw and take more than a week to heal.’
      • ‘The fragile reinforced concrete elements were repaired and protected through new chemical treatments.’
      • ‘He appears to be motivated to confront his problems and is willing to participate in all forms of recommended treatment, including chemical castration.’
      • ‘Practical control of premature sprouting in storage is achieved through the use of low temperatures or treatment with chemical sprout suppressants.’
      • ‘For faster fading, your dermatologist may prescribe a stronger lightener, chemical peel, laser treatment or even a combination of the three.’
      • ‘These are chemical substances that when added to the analyte, change color at the equivalence point.’
    2. 1.2Relating to, involving, or denoting the use of poison gas or other chemicals as weapons of war.
      ‘the manufacture of chemical weapons’
      • ‘He has had chemical weapons and he's used them.’
      • ‘It has been alleged in the course of the raids that chemical weapons and napalm bombs were also used.’
      • ‘What's your take on the effectiveness of bio and chemical terror weapons?’
      • ‘Nuclear and chemical weapons are definitely human products.’
      • ‘Aside from the nuclear variety of WMD, biological and chemical weapons pose serious dangers.’
      • ‘They have every incentive to cooperate with us because these are people who are promising to, you know, detonate dirty bombs or chemical weapons and the like in Europe.’
      • ‘Unlike biological and chemical weapons, however, they affect humans indirectly rather than directly.’
      • ‘Fear grows when Harry begins showing signs of nerve gas poisoning, suggesting a chemical weapon attack’
      • ‘It is possible that the leader gave orders to torch oil wells, launch chemical weapons or fire missiles, but that the commands were ignored, he added.’
      • ‘The specter of biological or chemical weapons being used in terrorist attacks substantially raises the possibility of widespread human and social destruction.’
      • ‘The north has responded with mysterious plans using thousands of commandos and chemical weapons.’
      • ‘Never develop, produce, acquire, stockpile, transfer, or retain chemical weapons or help anyone to do so.’
      • ‘Wait, they're going to poison us with chemical weapons!’
      • ‘They have not sold anyone chemical weapons, as far as anyone knows.’
      • ‘The next adversary may use chemical weapons or pull its main forces into urban areas to fight to the bitter end.’
      • ‘In previous wars it took large artillery bombardments to make chemical weapons effective.’
      • ‘And for the record I do think he had WMD - chemical weapons in particular.’
      • ‘The war that followed saw them employing chemical weapons and both sides firing ballistic missiles at major cities.’
      • ‘We know that he's rushing hard to try to get a nuclear capability, that he is building biological and chemical weapons and has missiles with which to deliver those.’
      • ‘Even the use of chemical or biological weapons is problematic.’


  • A compound or substance that has been purified or prepared, especially artificially.

    ‘never mix disinfectant with other chemicals’
    ‘controversy arose over treatment of apples with this chemical’
    • ‘There is often more than one synthetic route for preparing a desired chemical.’
    • ‘Any scientist, organization, or member of the public may nominate a chemical for NTP testing.’
    • ‘Toxic chemicals such as benzene, toluene and methyl benzene were included in the list.’
    • ‘The other chemical is an estrogen-like compound in women's urine.’
    • ‘Also, the chemical plant was processing ammonium nitrate, a stable chemical that requires a substantial infusion of energy to explode.’
    • ‘Once in place, it expects chemical companies to volunteer to test specific chemicals.’
    • ‘A battery is basically a simple electrochemical device to store electrical energy as chemicals.’
    • ‘If the other chemical was using those electrons to hold it together, it would fall apart.’
    • ‘It is an organic chemical produced by reacting chlorine gas with phenol.’
    • ‘Chlorine is a basic industrial chemical, prepared in immense quantities by electrolysis of brine.’
    • ‘It stores and processes hundreds of tonnes of toxic and highly inflammable chemicals and compounds.’
    • ‘Every pit or track contains a certain chemical that reacts to protein matrices.’
    • ‘However, aquatic life is much more sensitive to even these low levels of toxic chemicals, Pardue says.’
    • ‘Alcohol contains ethanol, a chemical that causes blood vessels to expand, which can give you a headache.’
    • ‘Breakfast cereals and breads also contain substantial quantities of the chemical.’
    • ‘If the burning chemical is a powder-like substance such as lime, brush it off the skin before flushing.’
    • ‘Benzene, a chemical in detergents and oven cleaners, is also known to be a carcinogen.’
    • ‘Each year, there is more sulfuric acid produced in the United States than any other chemical.’
    • ‘Tannic acid, or tannin, is the same chemical used in tanning animal hides.’
    • ‘Quite apart from this, artificial fluoride is a toxic chemical which we neither need nor want in our public water supplies.’


Late 16th century: from French chimique or modern Latin chimicus, chymicus, from medieval Latin alchymicus, from alchimia (see alchemy).