assumption
n. countablen. something that you believe is true even though you have no proof yet. You use this when you start a task or an argument by taking a fact for granted.
n. a belief or proposition accepted as true or as certain to happen, without proof. Often serves as the premise for a logical argument or a plan of action.
My plan is based on the assumption that the weather stays clear.
The manager made a false assumption about the team's availability, which led to a major scheduling conflict.
Scientific progress often requires us to challenge a fundamental assumption that has been treated as an absolute truth for decades, opening the door to entirely new paradigms.
Commonly paired with the preposition 'on' ('based on the assumption') or followed by a 'that' clause.
make an assumption about that he is richmake an assumption that he is richWhen followed by a clause, the noun takes 'that' directly rather than a prepositional phrase.