Hann function

Etymology
Named after the Austrian meteorologist.

Noun

 * 1)  A discrete window function, $$w(n)= \frac{1}{2}\; \left(1 - \cos \left ( \frac{2 \pi n}{N-1} \right) \right)$$, typically used to select a subset of a series of samples in order to perform a Fourier transform or other calculation.