Focus on the pronunciation of theory
English definition of “theory”
/ˈθɪər·i/, /ˈθi·ə·ri/ n [C/U]
› something suggested as a reasonable explanation for facts, a condition, or an event, esp. a systematic or scientific explanation: [U] Adele took a course in modern political theory. [C] I have a theory (= an opinion) about why everybody in the city is in such a hurry.