Turkey
turd.
Turbulent means stormy and starts with the letters TU.
a tunic
Tunis is the capital city of Tunisia. It begins with the letters TU.
Probably you are thinking of "as-tu" which is the inverted form of "tu as" as used in questions like: "Quel age as-tu?" (literally: What age have you? - figuratively: How old are you?)
Perhaps you mean a tureen.
The question 'Quel 'a' as-tu?' asks What [letter] 'a' [word] do you have? In the word-by-word translation, the interrogative pronoun 'quel' means 'what, which'. The noun 'a' means 'the letter a'. The verb 'as' means '[you] have'. And the personal pronoun 'tu' means 'you'.
tuberculosis
tu tu
Turtle and a tuatara.
tuberculosis
Tuvalu