Question on the "butter" function

Hello everybody.

I tried to use the function butter to get the coefficients of a digital butterworth filter.

I tried to fix bandwidth B and center frequency fc to some values giving a ratio fc/B, so the Q-factor, different from 1/sqrt(2) and it works.

Are we still talking about a Butterworth filter in such a case?! (or maybe the definition I'm using to identify the Butterworth filter is wrong xD)

Thanks in advance. Cheers