English Reference
noun

assumption

n.
US /əˈsəmpʃən/ UK /ɐsˈʌmpʃən/ as·sump·tion UK spelling assumption's, assumption's

  1. 01 B2 Upper Intermediate

    something that you accept as true or certain to happen, even if you do not have any proof.

    a belief or proposition accepted as true or as certain to happen, without proof or demonstration.

    Simple

    The whole plan was based on the assumption that the weather would stay fine.

    In context

    The economic forecast relies on the flawed assumption that consumer spending will remain stable despite rising interest rates.

    suppositionpresumptionbelief
  2. 02 C1 Advanced Formal

    the act of taking a position of power or starting a new responsibility.

    the act of taking on or adopting a role, responsibility, or position of power.

    Simple

    His assumption of the role of manager surprised everyone in the office.

    In context

    The sudden assumption of emergency powers by the president triggered widespread protests across the capital.

    Usage

    Often followed by the preposition 'of'.

    relinquishmentsurrender
  3. 03 C2 Proficiency Formal Religion

    the belief in some Christian churches that Mary, the mother of Jesus, was taken into heaven.

    the doctrine or festival commemorating the bodily taking up of the Virgin Mary into heaven.

    Simple

    Many countries have a public holiday in August to celebrate the Assumption.

    In context

    The cathedral features a stunning Renaissance painting depicting the Assumption of the Virgin surrounded by angels.

Usage additional assumption · assumption hold · assumption imply

Under New York State’s Medicaid-funded homecare system, employers must pay wages for 13 hours of a 24-hour shift, under the assumption that workers use the remaining 11 hours to eat and sleep.

UN News· 13 Aug 2026

And this non-appearance presents a more serious challenge to modern scientific assumptions than any UFO sighting.

The Guardian· 11 Aug 2026
This entry
Level B2 · Upper Intermediate
Frequency Common
Updated