theory
UK: ˈθɪəri | US: ˈθiːəri
n. a system of ideas intended to explain something, based on general principles
n. a speculative or abstract thought
n. (mathematics/science) a coherent set of propositions used as principles of explanation
The word "theory" traces back to the Greek theōria (θεωρία), meaning "contemplation" or "speculation," derived from theōros (θεωρός, "spectator"). The root theor- originally referred to observing religious festivals or philosophical inquiry. Over time, Latin (theoria) and later Old French (theorie) adapted it to denote intellectual examination. By the 16th century, English adopted it to describe systematic explanations, reflecting its evolution from passive observation to active conceptual frameworks.
Einstein’s theory of relativity revolutionized physics.
Her approach blends practice with theory.
The detective developed a theory about the crime.
In theory, the plan should work, but reality may differ.
The course covers both classical and modern economic theories.