How to name a part of a piechart
Solution 1:
The correct term is slice, fitting the pie metaphor.
Solution 2:
Since each "part" is a sector of a circle, sector can be used IMO.
Solution 3:
I think the word "segment" would usually be used.
Solution 4:
All the ones mentioned are fine. You can also call it wedge, especially with 3D pies. One that is pulled out is called exploded wedge.