The range around an inflation target within which the central bank need not act
The margin either side of an inflation target, such as India's 2 to 6 % around a 4 % target.
Some central banks are given a band rather than a point. The Reserve Bank of India targets 4 % with a band of two points either side; if inflation stays outside it for three quarters the bank must account for the failure. The upper edge of such a band is a natural threshold for an inflation indicator.