I've heard people in the forums suggesting it should be called Farenheit, but I don't remember it being mentioned in FFX-2.

The name was on the box in the same location that Sister Ray and Fenrir were on models of the same from FFVII and AC, respectively.

It seems that it was approved by Square, so they seem to be tacitly agreeing with the name, even if they didn't pick it.

And the circle thing makes sense. It would be called a rotary here (pronounced 'road-tree').