You either (i) don't know the Greek alphabet, or (ii) can't read people's short posts. I literally mentioned tau and why it might be a silly name (it clashes with other mathematical uses of the symbol tau).
> In another comment, I asked why people chose to use the symbol τ over just writing turn or "rev(olution)" (defined to be the constant ≈ 6.28318530718) given how unambiguous the latter is as a name for 2π. And why not just write sinrev() or sinturn(), and leave the symbols sin() and rev (defined to be ≈ 6.28318530718) alone?
You were asking why they used the symbol τ rather than the words "rev" or "turn". You didn't give a clue that you knew any of the rest, including what the symbol meant.
[0] https://en.wikipedia.org/wiki/Tau_(mathematics)