Final answer:
The term Mexihco, referring to the Valley of Mexico, the heartland of the Aztec Empire, is from the Nahuatl language, which was spoken by the Mexica or the Aztecs.
Step-by-step explanation:
The term Mexihco refers to the heartland of the Aztec Empire, specifically the Valley of Mexico, and is a word from the Nahuatl language. Nahuatl was spoken by the Mexica, better known as the Aztecs, who settled and built the city of Tenochtitlan in 1325 on a swampy island in Lake Texcoco.
This city eventually became the center of the Aztec Empire, a mighty civilization with a complex social system and rich cultural heritage, until the Spanish conquest in the 16th century.