An example of extensive is a report on owls with information about every type of owl.
The hospital was much more extensive than I expected.
I didn't know he had such an extensive library.
Extensive coal mines are in the vicinity, and there are manufactures of iron and steel, mill machinery, door and sash factories, etc., as well as several shipbuilding yards.
Extensive works have been carried out along the sea front.
Not only is his vocabulary very extensive, but his employment of it extraordinarily bold and unconventional.