incenter

The incenter of a geometrical shape is the center of theincircle (if it has any). The radius of the incircle is sometimescalled the inradius.

On a triangle the incenter always exists and it is the intersectionpoint of the three internal angle bisectors. So in the next picture,$AX,BY,CZ$ are angle bisectors, and $AB,BC,CA$ are tangent to thecircle.