1. An area of land or territory that has not been officially surveyed, mapped, or measured
The expedition ventured into the unsurveyed zone of the Amazon rainforest.
A expedição aventurou-se na zona não mapeada da floresta amazônica.
2. A region whose boundaries, topography, or boundaries have not been formally documented
Several unsurveyed zones remain in the remote mountains of Central Asia.
Várias zonas não mapeadas permanecem nas montanhas remotas da Ásia Central.