Added 9 October 2026
theory
/ˈθɪə.ɹi/ noun
In Latin: theōria Wiktionary
noun Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about theory at Wordnik → Where our words come from →
-
A well-substantiated explanation of some aspect of the natural world; an organized system of accepted knowledge that applies in a variety of circumstances to explain a specific set of phenomena.
theories can incorporate facts and laws and tested hypotheses
-
A tentative insight into the natural world; a concept that is not yet verified but that if true would explain certain facts or phenomena.
a scientific hypothesis that survives experimental testing becomes a scientific theory
-
A belief that can guide behavior.
the architect has a theory that more is less
Origin
Ancient Greek *θεᾱ-(ϝ)ορός, *θεη-(ϝ)ορός (*theā-(w)orós, *theē-(w)orós) Borrowed from Middle French théorie, a learned borrowing from Late Latin theōria, borrowed from Ancient Greek θεωρία (theōría), from θεωρός (theōrós, “spectator”) + -ῐ́ᾱ (-ĭ́ā).
From Wiktionary, via Kaikki.org (CC BY-SA)