terra in·cog·ni·ta 
(ĭn′kŏg-nētə, -kŏgnĭ-tə)
(ĭn′kŏg-nētə, -kŏgnĭ-tə)n. pl. terrae in·cog·ni·tae (ĭn′kŏg-nētē, -kŏgnĭ-tē′)
1. An unknown land; an unexplored region: "a vast and virtually final terra incognita left to terrestrial explorers" (David F. Salisbury).
2. A new or unexplored field of knowledge.
[New Latin : Latin terra, land + Latin incognita, feminine of incognitus, unknown.]