highly significant or important especially bringing about or marking the beginning of a new development or era; "epochal decisions made by Roosevelt and Churchill"; "an epoch-making discovery"
large in spatial extent or range or scope or quantity; "an extensive Roman settlement in northwest England"; "extended farm lands"; "surgeons with extended experience"; "they suffered extensive damage"
of agriculture; increasing productivity by using large areas with minimal outlay and labor; "producing wheat under extensive conditions"; "agriculture of the extensive type"