1) Circularity 2) Disk shape 
• (n.) The state of being concentric.
The permissible variation in the location of the axis (exact center) of a characteristic to the axis of another characteristic. The axis of the controlled characteristic must remain within a circular zone of a diameter equal to the concentricity limit
Con`cen·tric'i·ty noun The state of being concentric. 
[n] - the quality of having the same center (as circles inside one another)
For a container, the shape in which various cross sections have a common center.
noun the quality of having the same center (as circles inside one another)
When the parts share the same center line they are concentric to each other.
Relationship of all inside dimensions to all outside dimensions usually as with diameter expressed in thousandths of an inch TIR (Total Indicator Reading)