0 a round handle, or a small, round device for controlling a machine or electrical equipment -- 球形把手；（机器等的）旋钮
1 a small amount of something solid, especially butter -- （尤指黄油）小块
2 a penis -- 阴茎
Twiddle a knob on a radio in Britain and you may hear more voices speaking crackly French or German than English.
At the twiddle of a knob the operators can focus on a tiny amount of airspace or scan the whole area.
