supposition

/ˌsʌpəˈzɪʃən/

Misollar

That's a supposition, not a fact.
This supposition, that the Earth is immobile, was completely untrue.

ot noun

Something that is supposed; an assumption made to account for known facts, conjecture.
The act or an instance of supposing.

Manbalar: Wiktionary (Free Dictionary API orqali), Datamuse, Tatoeba (CC BY 2.0 FR), MyMemory.