Definition of assumption in US English:



  • 1A thing that is accepted as true or as certain to happen, without proof.

    ‘they made certain assumptions about the market’
    with clause ‘we're working on the assumption that the time of death was after midnight’
    • ‘Unless all of these assumptions are true, mass surveillance would be of very little help.’
    • ‘Scientists reconsidered earlier assumptions about the function of sex hormones as well.’
    • ‘Their success immediately exposed the flawed assumptions of previous generations.’
    • ‘Yet another unstated assumption is that the only way to prevent aircraft crashing into populated areas is by regulation.’
    • ‘Many of the key assumptions used as the basis for safety claims have been overturned.’
    • ‘And everything that happened in our part of the world reinforced this assumption.’
    • ‘Taste is based upon a certain set of assumptions about what is good or bad in the world.’
    • ‘That was the theory but, like so many assumptions about war, it does not stand up in practice.’
    • ‘These rules are complicated and couples in divorce proceedings should make no assumptions.’
    • ‘Every now and again you read a book that shatters assumptions you have held for a long time.’
    • ‘There is a frequent and incorrect assumption that ecological buildings have to be far more expensive.’
    • ‘Perhaps you should question your own assumptions about that before you go poking about in mine.’
    • ‘Wrong assumptions about an employee's commitment to work frequently lead to problems.’
    • ‘We need to clarify the assumptions inherent in this argument before we can determine its validity.’
    • ‘This policy is based on the extremely short-sighted assumption that a terrorist needs to push buttons to make a bomb explode.’
    • ‘It is high time that our cultural assumptions caught up with that reality.’
    • ‘Working on this assumption, we continued our fieldwork along the outskirts of Starosel.’
    • ‘There were so many gross assumptions in her letter that it is hard to know where to start.’
    • ‘In other words, I disagree with just about all the assumptions on which this proposal is based.’
    • ‘What you have to ask is: how realistic are the assumptions these companies are working with?’
    • ‘The assumption is, presumably, that advertising will be used to sell these cars.’
    • ‘It is a fair question, but we should not overlook the assumptions that underlie it.’
    supposition, presupposition, presumption, premise, belief, expectation, conjecture, speculation, surmise, guess, theory, hypothesis, postulation, conclusion, deduction, inference, thought, suspicion, notion, impression, fancy
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  • 2The action of taking on power or responsibility.

    ‘the assumption of an active role in regional settlements’
    • ‘This assumption of responsibility gave rise to a relationship of trust and confidence between these parties.’
    • ‘Surrender is not the same as shirking one's responsibilities or assumption of passivity.’
    • ‘Others welcomed Hitler's assumption of power, seeing in it a chance to advance their own careers.’
    • ‘The assumption of direct power by the crown was not wholly welcomed by settlers.’
    • ‘Upon Yushchenko's assumption of the presidency he immediately arranged to visit Moscow.’
    • ‘The judiciary was badly split by the military's May 29 assumption of executive power.’
    • ‘There are a number of references in the speeches in this case to voluntary assumption of responsibility.’
    • ‘We are deeply concerned by the King's assumption of power on 1 March, which will increase the risk of instability in the country and undermine the institutions of democracy and constitutional monarchy.’
    • ‘Good intentions will always be pleaded for any assumption of power.’
    acceptance, shouldering, handling, managing, tackling, taking on
    seizure, seizing, taking, taking over, taking away, appropriation, appropriating, commandeering, expropriation, expropriating, confiscation, confiscating, requisition, requisitioning, hijack, hijacking, wresting, usurping, pre-empting, arrogation, claiming
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  • 3The reception of the Virgin Mary bodily into heaven. This was formally declared a doctrine of the Roman Catholic Church in 1950.

    • ‘Cornwell vividly describes the local worship - for instance, following an open coffin containing an effigy of the dead Virgin before her Assumption into heaven.’
    • ‘The church has proclaimed as infallible two dogmas in relation to Mary - the Immaculate Conception and the Assumption.’
    • ‘The Immaculate Conception and the Assumption are rooted in the patristic axiom that Mary was the worthy Mother of God, a worthy tabernacle of the Most High.’
    • ‘Pope Pius XII infallibly proclaimed the doctrine of the Assumption of the Blessed Virgin Mary on 1 November 1950.’
    • ‘His Requiem Mass was celebrated in the Church of the Assumption of the Blessed Virgin Mary.’
    • ‘The Virgin birth, the bodily Assumption of the Blessed Virgin Mary, the Resurrection of Jesus, the survival of our own souls after death: these are all claims of a clearly scientific nature.’
    • ‘Finally, in the seventh, A Prayer for my Daughter, the author instructs his child not to believe in the Assumption of the Virgin Mary.’
    • ‘On August 15, we will celebrate the feast of Mary's Assumption into heaven.’
    1. 3.1 The feast in honour of the Assumption, celebrated on 15 August.
      • ‘Liechtenstein´s national day is celebrated on Assumption Day.’
      • ‘It does not surprise me in the least that he was present at the traditional Mass for the Assumption.’
      • ‘Here is the audio sermon for the Assumption.’
      • ‘The Feast of the Assumption was celebrated with prayers at the Marian Shrine in the village last Sunday after 10.00 am mass.’
      • ‘The date was August 15, 1975, the Feast of the Assumption.’
      • ‘The feast celebrated in the Byzantine calendar as the Dormition on 15 August became the Assumption and Coronation of the Virgin in the west.’
      • ‘I haven't been feeling well since we got back from our trip so Rocky and I went to the Vigil Mass for the Assumption.’
      • ‘Since the opening ceremonies on the Feast of the Assumption, August 15, there has been a steady flow of people, both young and old, arriving in Ladywell to pray at the Shrine and sip water from the Holy Well.’
  • 4archaic Arrogance or presumption.


Middle English (in assumption (sense 3)): from Old French asompsion or Latin assumptio(n-), from the verb assumere (see assume).