This is the 9630th most frequent Turkish word.
anladın
"You understood."
The word 'anladın' means 'you understood' in this context, inferring the completion of the understanding after an action.
Bu kitabı dikkatlice okudun ve sonunda her şeyi anladın.
You read this book carefully and finally understood everything.
Here, 'anladın' is used in an interrogative form, asking whether the understanding has occurred.
Anladın mı, neden bunu yapman gerektiğini?
Did you understand why you needed to do this?
In this sentence, 'anladın' expresses confirmation of understanding after an explanation.