Definition of equation in English:



  • 1Mathematics
    A statement that the values of two mathematical expressions are equal (indicated by the sign =).

    • ‘These laws are very precise and can be expressed by exact mathematical equations.’
    • ‘The sections on equations cover quadratic equations where he discusses two solutions.’
    • ‘Lagrange's main object was to find out why cubic and quartic equations could be solved algebraically.’
    • ‘The first person known to have solved cubic equations algebraically was del Ferro but he told nobody of his achievement.’
    • ‘An encryption algorithm is a mathematical equation containing the message being encrypted or decrypted.’
    • ‘It also contains continued fractions, quadratic equations, sums of power series and a table of sines.’
    • ‘Now express the pattern as a mathematical equation.’
    • ‘He replaced the differential operator d/dx by a variable p transforming a differential equation into an algebraic equation.’
    • ‘When I pressed him to write an equation expressing the value for a, he insisted that he would need a symbol for within.’
    • ‘The movement associated with each mode can be expressed by the motion equation for a single degree-of-freedom system.’
    mathematical problem, sum, calculation, question
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  • 2mass noun The process of equating one thing with another.

    ‘the equation of science with objectivity’
    • ‘I say two, because another managerial solution to this quandary is to work on the slightly simpler equation of four into three.’
    • ‘One-half of the general problem of stellar atmospheres revolves around the solution of the equation of radiative transfer.’
    • ‘As relationships go, I realized this simple equation of life.’
    • ‘And can you tell us, are you concerned about second-guessing on that whole equation?’
    • ‘The simple equation of balancing caloric intake and exercise is the key to fitness.’
    • ‘I feel that I have developed some sort of equation with them.’
    • ‘The facts reduce themselves to a terrible equation of time and consequence.’
    equating, equalization, identification, association, connection, likening, matching
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    1. 2.1the equation A situation in which several factors must be taken into account.
      ‘money also came into the equation’
      • ‘It doesn't enter into the equation, because it's not part of the culture.’
      • ‘And the small matter of lost tax revenue doesn't enter into the equation at all, of course.’
      • ‘Another factor in the equation: Used equipment must compete with new equipment in the marketplace.’
      • ‘In these and other ways, care theorists distance themselves from any simple equation of subjective hurt and moral claims.’
      • ‘So let me analyse the business element of that equation.’
      • ‘The current price of oil, states the release, is a critical ingredient in the tourism industry and must be factored into the equation.’
      • ‘Yet rising U.S. interest rates and a still-strong dollar must be factored into that equation.’
      • ‘When pressure of competition was factored into the equation, the situation changed.’
      • ‘The second part of that equation seems to have been abandoned by feminists early on.’
      • ‘The fact that he might have to do without doesn't enter into the equation for some in the animal protection industry.’
      • ‘We have explained the process of the enabling development equation.’
      • ‘So the children issue doesn't really enter into the equation.’
      • ‘Even the simplest of pots was a chore and ‘position’ did not even enter into the equation.’
      • ‘This deprivation of culture, of identity, is the missing link in Africa's development equation.’
      • ‘The perception of our success up to this point will be a critical part of that equation.’
      • ‘It was a simple and compelling equation: the bigger the wave the better your bottom-line.’
      • ‘Once all that is figured out, the most confusing factor in the equation must be pondered: playing time.’
      • ‘Concern for life just does not belong in the profit/loss equation.’
      • ‘Even on stark issues like abortion, there can be no simple equation between the church and any political program or party.’
      • ‘Food/energy balance is the simple equation of calories in/calories out.’
      the situation, the problem, the case, the question, the quandary, the predicament
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  • 3Chemistry
    A symbolic representation of the changes which occur in a chemical reaction, expressed in terms of the formulae of the molecules or other species involved.

    • ‘The final system is the aerobic system. aerobic meaning it requires oxygen as part of its chemical equation to function.’
    • ‘I asked as I balanced a chemical equation and answered some questions.’
    • ‘The isotopic data do not conform to a simple mixing equation.’
    • ‘When hydrolysis occurs, we will write a chemical equation to describe it, and new species will be formed in solution.’
    • ‘The chemical equations for some reactions may have a lone reactant or a single product.’


  • equation of the first (or second etc.) order

    • An equation involving only the first derivative, second derivative, etc.

      • ‘Special attention should be drawn also to his little known pamphlet on regular point of linear differential equations of the second order used for a number of years in connection with one of his courses of lectures.’
      • ‘His doctoral dissertation was on the theory of the propeller which led to his developing a theory of partial differential equations of the second order.’
      • ‘This integral was introduced in a paper on differential equations of the second order which he wrote in 1870.’
      • ‘He did this by using an indeterminate equation of the second order, Nx 2 + 1 = y 2, where N is the number whose square root is to be calculated.’
      • ‘He began mathematical research while still an undergraduate and his first paper, On the isoclinal lines of a differential equation of the first order was published in the Proceedings of The Royal Society of Edinburgh in 1903.’


Late Middle English: from Latin aequatio(n-), from aequare ‘make equal’ (see equate).