Detail from "The mythical island of Thule on the Carta Marina", 1539 by Olaus Magnus, depicting creatures inhabiting mare incognita, from an old icelandic map.
Terra incognita "land unknown"; Terra incognita (with incognita stressed on its second syllable in Latin, but with variation in pronunciation in English) is the Latin term for "unknown land", used in cartography for regions that have not been mapped or documented. The expression is not found in ancient texts, and occurs first in the sixteenth century.