Google. Hybrid filters combine digital and analog filters. Except when they do not. Because there is not just one definition for "hybrid filter". All you can say is that hybrid filters combine two different methods of doing something.
Using two different filters does not mean that you are using a hybrid filter. If you have a digital high-pass filter and a digital low-pass filter and put them together then you end up with either a band-pass filter or a notch filter, which could be combined into a single more complicated digital filter, so you really have only used one kind of filter in that situation. Your filters have to work differently to qualify as a hybrid filter.
