Returning for the nth time

Solution 1:

You've gone to the store at a few times, t1, t2, t3, t4,...

t1 is the first time, t2 is the second time etc.

Did you return to the store at time t1? No, the meaning of 'return' is that you've been there at least once and you've visited again.

At time t2, can you say you've returned? Yes. Is t2 the first time you've returned? If you haven't visited the store anytime between t1 and t2, then yes.

On t3, how many times have you visited the store? Three. How many times have you returned to the store. Two times. So at time t3 you're retuning to the store the second time.

Solution 2:

It is not a silly question. I think these expression are ambiguous, and different people (or different contexts) may interpret them inconsistently.