Pronunciation: (tit"i-kä'ku; Sp. tē"tē-kä'kä),[key] —n. Lake, a lake on the boundary between S Peru and W Bolivia, in the Andes: the largest lake in the region; the highest large lake in the world. 3200 sq. mi. (8290 sq. km); 12,508 ft. (3812 m) above sea level.