...well sort of complicated for me.
I live with my grandparents, who I call Nan and Pop (and refer to them by that too).
And then there's my mother, who I sometimes refer to by her first name or "my mother", idk depends. My Dad, I used to call Dad, but now I never see him so don't really need to say that. Oh and when talking directly to my mother, I don't call her anything.