An assumption is something that you assume to be the case, even without proof. For example, people might make the assumption that you're a nerd if you wear glasses, even though that's not true. Or very nice.

From the Latin assumptionem, meaning “a taking or receiving,” assumption was recorded circa 1300 as a noun describing “the reception of the Virgin Mary into heaven.” The word later shook its religious roots and developed into the noun we hear more often today, usually when a person takes something for granted or literally takes possession of something.

Primary Meanings of assumption

the act of assuming or taking for granted
the act of taking possession of or power over something
audacious (even arrogant) behavior that you have no right to
Full Definitions of assumption

n the act of assuming or taking for granted

“your assumption that I would agree was unwarranted”
the act of positing; an assumption taken as a postulate or axiom
Type of:
act, deed, human action, human activity
something that people do or cause to happen

n a statement that is assumed to be true and from which a conclusion can be drawn

“on the assumption that he has been injured we can infer that he will not to play”
premise, premiss
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major premise, major premiss
the premise of a syllogism that contains the major term (which is the predicate of the conclusion)
minor premise, minor premiss, subsumption
the premise of a syllogism that contains the minor term (which is the subject of the conclusion)
an unproved statement put forward as a premise in an argument
condition, precondition, stipulation
an assumption on which rests the validity or effect of something else
a postulated sequence of possible events
boundary condition
(mathematics) a condition specified for the solution to a set of differential equations
provision, proviso
a stipulated condition
Type of:
posit, postulate
(logic) a proposition that is accepted as true in order to provide a basis for logical reasoning

n a hypothesis that is taken for granted

“any society is built upon certain assumptions
supposal, supposition
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an intuitive assumption
base, basis, cornerstone, foundation, fundament, groundwork
the fundamental assumptions from which something is begun or developed or calculated or explained
given, precondition, presumption
an assumption that is taken for granted
basic assumption, constatation, self-evident truth
an assumption that is basic to an argument
non sequitur
(logic) a conclusion that does not follow from the premises
meat and potatoes
the fundamental part
Type of:
hypothesis, possibility, theory
a tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena

n the act of taking possession of or power over something

“his assumption of office coincided with the trouble in Cuba”
“the Nazi assumption of power in 1934”
“he acquired all the company's assets for ten million dollars and the assumption of the company's debts”
laying claim
Type of:
the act of contracting or assuming or acquiring possession of something

n audacious (even arrogant) behavior that you have no right to

effrontery, presumption, presumptuousness
uppishness, uppityness
assumption of airs beyond one's station
Type of:
audaciousness, audacity
aggressive boldness or unmitigated effrontery

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