Normal polarity refers to the orientation of the Earth’s magnetic field in the same direction as the present magnetic field, where the magnetic north pole is near the geographic north pole. This concept is important in paleomagnetism for understanding the history of Earth’s magnetic field and the process of geomagnetic reversals.
Reference: Butler, R. F. (1992). “Paleomagnetism: Magnetic Domains to Geologic Terranes.” Blackwell Science.